Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-07-03 Thread Rob Clark
On Fri, Jul 3, 2015 at 8:32 AM, Thierry Reding  wrote:
> On Tue, Jun 30, 2015 at 11:04:45AM +0200, Daniel Vetter wrote:
>> On Tue, Jun 30, 2015 at 10:31 AM, Benjamin Gaignard
>>  wrote:
>> > I think that what have been done by Rob with module_param is also a good 
>> > idea:
>> > https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/gpu/drm/msm/msm_drv.c?id=e90dfec78ec288d6c89a7b508a5c5d4ae8b7f934
>> >
>> > Can you mix compilation flag and module param ?
>>
>> Hm, the point of the kconfig is to not require all the legacy baggage
>> from fbdev. But I guess a module option could be added later on too.
>> bochs has it too.
>
> I think the option would primarily be useful for testing. I've often
> needed to test modesetting code without fbdev getting in the way and the
> only way to currently do that is by recompiling with legacy fbdev
> disabled. The option would allow an fbdev-enabled kernel to be used but
> disable the fbdev code if desired.

and for debugging.. when things are going wrong it's nice for the
first modeset to not happen under console_lock ;-)

BR,
-R

> Thierry
>
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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-07-03 Thread Thierry Reding
On Tue, Jun 30, 2015 at 11:04:45AM +0200, Daniel Vetter wrote:
> On Tue, Jun 30, 2015 at 10:31 AM, Benjamin Gaignard
>  wrote:
> > I think that what have been done by Rob with module_param is also a good 
> > idea:
> > https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/gpu/drm/msm/msm_drv.c?id=e90dfec78ec288d6c89a7b508a5c5d4ae8b7f934
> >
> > Can you mix compilation flag and module param ?
> 
> Hm, the point of the kconfig is to not require all the legacy baggage
> from fbdev. But I guess a module option could be added later on too.
> bochs has it too.

I think the option would primarily be useful for testing. I've often
needed to test modesetting code without fbdev getting in the way and the
only way to currently do that is by recompiling with legacy fbdev
disabled. The option would allow an fbdev-enabled kernel to be used but
disable the fbdev code if desired.

Thierry


pgp7NTiItVHYl.pgp
Description: PGP signature


Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-07-03 Thread Thierry Reding
On Tue, Jun 30, 2015 at 11:04:45AM +0200, Daniel Vetter wrote:
 On Tue, Jun 30, 2015 at 10:31 AM, Benjamin Gaignard
 benjamin.gaign...@linaro.org wrote:
  I think that what have been done by Rob with module_param is also a good 
  idea:
  https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/gpu/drm/msm/msm_drv.c?id=e90dfec78ec288d6c89a7b508a5c5d4ae8b7f934
 
  Can you mix compilation flag and module param ?
 
 Hm, the point of the kconfig is to not require all the legacy baggage
 from fbdev. But I guess a module option could be added later on too.
 bochs has it too.

I think the option would primarily be useful for testing. I've often
needed to test modesetting code without fbdev getting in the way and the
only way to currently do that is by recompiling with legacy fbdev
disabled. The option would allow an fbdev-enabled kernel to be used but
disable the fbdev code if desired.

Thierry


pgp7NTiItVHYl.pgp
Description: PGP signature


Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-07-03 Thread Rob Clark
On Fri, Jul 3, 2015 at 8:32 AM, Thierry Reding thierry.red...@gmail.com wrote:
 On Tue, Jun 30, 2015 at 11:04:45AM +0200, Daniel Vetter wrote:
 On Tue, Jun 30, 2015 at 10:31 AM, Benjamin Gaignard
 benjamin.gaign...@linaro.org wrote:
  I think that what have been done by Rob with module_param is also a good 
  idea:
  https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/gpu/drm/msm/msm_drv.c?id=e90dfec78ec288d6c89a7b508a5c5d4ae8b7f934
 
  Can you mix compilation flag and module param ?

 Hm, the point of the kconfig is to not require all the legacy baggage
 from fbdev. But I guess a module option could be added later on too.
 bochs has it too.

 I think the option would primarily be useful for testing. I've often
 needed to test modesetting code without fbdev getting in the way and the
 only way to currently do that is by recompiling with legacy fbdev
 disabled. The option would allow an fbdev-enabled kernel to be used but
 disable the fbdev code if desired.

and for debugging.. when things are going wrong it's nice for the
first modeset to not happen under console_lock ;-)

BR,
-R

 Thierry

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 dri-de...@lists.freedesktop.org
 http://lists.freedesktop.org/mailman/listinfo/dri-devel

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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-06-30 Thread Archit Taneja

Hi,

On 06/30/2015 02:01 PM, Benjamin Gaignard wrote:

Hi,

I think that what have been done by Rob with module_param is also a good idea:
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/gpu/drm/msm/msm_drv.c?id=e90dfec78ec288d6c89a7b508a5c5d4ae8b7f934

Can you mix compilation flag and module param ?


I guess this won't be hard to do once we have a common fbdev emulation 
config option. We could consider this as a drm top level module param.


I'll keep this in mind.

Thanks,
Archit



Benjamin

2015-06-30 9:56 GMT+02:00 Archit Taneja :

Hi,

On 06/30/2015 12:40 PM, Daniel Vetter wrote:


Any updates on this or too much distractions? I really think doing
this would be awesome for the drm subsystem, instead of reinventing
this wheel for each driver.



I'd started on this again. I've got more free time now than before, so I
should have something in a week or so. I agree it will help a lot (there are
already two new drivers since we started discussing this!)

Archit



-Daniel

On Wed, Mar 25, 2015 at 10:21 AM, Daniel Vetter  wrote:


On Wed, Mar 25, 2015 at 01:47:54PM +0530, Archit Taneja wrote:


Hi,

On 03/13/2015 02:36 PM, Daniel Vetter wrote:


On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:




On 03/11/2015 08:47 PM, Daniel Vetter wrote:


On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:




On 03/10/2015 05:47 PM, Daniel Vetter wrote:


On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:


On 03/10/2015 03:35 PM, Daniel Vetter wrote:


On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:


On 03/10/2015 03:17 PM, Daniel Vetter wrote:


On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:


diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
 help
   FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool "Enable legacy fbdev support for your modesetting
driver"
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy
fbdev
+ support. Note that this support also provide the linux
console
+ support on top of your modesetting driver.



Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.



DRM_KMS_FB_HELPER selects that for us, right?



Hm right I've missed that. Reminds me that you need one more
patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all
drm
drivers. Otherwise this knob here won't work by default if you
e.g. select
radeon. In general we can't mix explicit options with menu
entries with a
select.



I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff
internally in
their respective xyz_fbdev.c files.



But with the stubbed out functions that should work, right? Why
doesn't
it?



There are still calls to functions from fb core like fb_set_suspend
and
register_framebuffer which aren't covered by the drm fb helper
functions.



Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?



There are a handful of fb core functions which are called by drm
drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release



Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include  from drivers into
drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include 
#else

/* static inline stubs for all the fb stuff used by kms drivers */
#endif

Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.



I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs
won't really work because struct declarations(like fb_info) also get
removed.

I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h
itself,
but that seemed a bit too intrusive.

This is what I'm currently doing:

- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap
would
actually benefit if we have drm fb helpers for them. They are used in
exactly the same manner by all the drivers.

- For the rest of the functions that are sparsely used, I was
considering
making very simple drm_fb_* wrapper functions. Something like:

void 

Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-06-30 Thread Daniel Vetter
On Tue, Jun 30, 2015 at 10:31 AM, Benjamin Gaignard
 wrote:
> I think that what have been done by Rob with module_param is also a good idea:
> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/gpu/drm/msm/msm_drv.c?id=e90dfec78ec288d6c89a7b508a5c5d4ae8b7f934
>
> Can you mix compilation flag and module param ?

Hm, the point of the kconfig is to not require all the legacy baggage
from fbdev. But I guess a module option could be added later on too.
bochs has it too.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-06-30 Thread Benjamin Gaignard
Hi,

I think that what have been done by Rob with module_param is also a good idea:
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/gpu/drm/msm/msm_drv.c?id=e90dfec78ec288d6c89a7b508a5c5d4ae8b7f934

Can you mix compilation flag and module param ?

Benjamin

2015-06-30 9:56 GMT+02:00 Archit Taneja :
> Hi,
>
> On 06/30/2015 12:40 PM, Daniel Vetter wrote:
>>
>> Any updates on this or too much distractions? I really think doing
>> this would be awesome for the drm subsystem, instead of reinventing
>> this wheel for each driver.
>
>
> I'd started on this again. I've got more free time now than before, so I
> should have something in a week or so. I agree it will help a lot (there are
> already two new drivers since we started discussing this!)
>
> Archit
>
>
>> -Daniel
>>
>> On Wed, Mar 25, 2015 at 10:21 AM, Daniel Vetter  wrote:
>>>
>>> On Wed, Mar 25, 2015 at 01:47:54PM +0530, Archit Taneja wrote:

 Hi,

 On 03/13/2015 02:36 PM, Daniel Vetter wrote:
>
> On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:
>>
>>
>>
>> On 03/11/2015 08:47 PM, Daniel Vetter wrote:
>>>
>>> On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:



 On 03/10/2015 05:47 PM, Daniel Vetter wrote:
>
> On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:
>>
>> On 03/10/2015 03:35 PM, Daniel Vetter wrote:
>>>
>>> On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:

 On 03/10/2015 03:17 PM, Daniel Vetter wrote:
>
> On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
>>
>> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
>> index 151a050..38f83a0 100644
>> --- a/drivers/gpu/drm/Kconfig
>> +++ b/drivers/gpu/drm/Kconfig
>> @@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
>> help
>>   FBDEV helpers for KMS drivers.
>>
>> +config DRM_FBDEV_EMULATION
>> +   bool "Enable legacy fbdev support for your modesetting
>> driver"
>> +   depends on DRM
>> +   select DRM_KMS_HELPER
>> +   select DRM_KMS_FB_HELPER
>> +   select FB_SYS_FILLRECT
>> +   select FB_SYS_COPYAREA
>> +   select FB_SYS_IMAGEBLIT
>> +   select FB_SYS_FOPS
>> +   select FB_CFB_FILLRECT
>> +   select FB_CFB_COPYAREA
>> +   select FB_CFB_IMAGEBLIT
>> +   default y
>> +   help
>> + Choose this option if you have a need for the legacy
>> fbdev
>> + support. Note that this support also provide the linux
>> console
>> + support on top of your modesetting driver.
>
>
> Maybe clarify that for linux console support you also need
> CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.


 DRM_KMS_FB_HELPER selects that for us, right?
>>>
>>>
>>> Hm right I've missed that. Reminds me that you need one more
>>> patch at the
>>> end to remove all the various select DRM_KMS_FB_HELPER from all
>>> drm
>>> drivers. Otherwise this knob here won't work by default if you
>>> e.g. select
>>> radeon. In general we can't mix explicit options with menu
>>> entries with a
>>> select.
>>
>>
>> I was trying that out. Removing DRM_KMS_FB_HELPER and having
>> DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff
>> internally in
>> their respective xyz_fbdev.c files.
>
>
> But with the stubbed out functions that should work, right? Why
> doesn't
> it?


 There are still calls to functions from fb core like fb_set_suspend
 and
 register_framebuffer which aren't covered by the drm fb helper
 functions.
>>>
>>>
>>> Hm, sounds like we need another patch to stub out fb_set_suspend when
>>> fbdev isn't enabled. Is there anything else?
>>
>>
>> There are a handful of fb core functions which are called by drm
>> drivers:
>>
>> fb_alloc_cmap/fb_dealloc_cmap
>>
>> fb_sys_read/fb_sys_write
>>
>> register_framebuffer/unregister_framebuffer/unlink_framebuffer/
>> remove_conflicting_framebuffers
>>
>> fb_set_suspend
>>
>> fb_deferred_io_init/fb_deferred_io_cleanup
>>
>> framebuffer_alloc/framebuffer_release
>
>
> Hm yeah that's somewhat annoying indeed. What about the following:
> 1. We move all the #include  from drivers into
> drm_fb_helper.h
>
> 2. Then we add stubs for these 

Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-06-30 Thread Archit Taneja

Hi,

On 06/30/2015 12:40 PM, Daniel Vetter wrote:

Any updates on this or too much distractions? I really think doing
this would be awesome for the drm subsystem, instead of reinventing
this wheel for each driver.


I'd started on this again. I've got more free time now than before, so I 
should have something in a week or so. I agree it will help a lot (there 
are already two new drivers since we started discussing this!)


Archit


-Daniel

On Wed, Mar 25, 2015 at 10:21 AM, Daniel Vetter  wrote:

On Wed, Mar 25, 2015 at 01:47:54PM +0530, Archit Taneja wrote:

Hi,

On 03/13/2015 02:36 PM, Daniel Vetter wrote:

On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:



On 03/11/2015 08:47 PM, Daniel Vetter wrote:

On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:



On 03/10/2015 05:47 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:

On 03/10/2015 03:35 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:

On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
  FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool "Enable legacy fbdev support for your modesetting driver"
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.


Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.


DRM_KMS_FB_HELPER selects that for us, right?


Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.


I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.


But with the stubbed out functions that should work, right? Why doesn't
it?


There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.


Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?


There are a handful of fb core functions which are called by drm drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release


Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include  from drivers into drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include 
#else

/* static inline stubs for all the fb stuff used by kms drivers */
#endif

Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.



I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs
won't really work because struct declarations(like fb_info) also get
removed.

I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h itself,
but that seemed a bit too intrusive.

This is what I'm currently doing:

- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap would
actually benefit if we have drm fb helpers for them. They are used in
exactly the same manner by all the drivers.

- For the rest of the functions that are sparsely used, I was considering
making very simple drm_fb_* wrapper functions. Something like:

void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)
{
   if (helper->fbdev)
   fb_deferred_io_init(helper->fbdev);
}

We could have all fb calls called within drm_fb_helper.c, creating
drm_fb_helper_* stub functions would then be an easier task. What do you
think?


That's actually an option I considered, but I hoped we could do it with
less work. If this indeed works and you can create the patch that would be
awesome.

Thanks, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch






--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux 

Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-06-30 Thread Daniel Vetter
Any updates on this or too much distractions? I really think doing
this would be awesome for the drm subsystem, instead of reinventing
this wheel for each driver.
-Daniel

On Wed, Mar 25, 2015 at 10:21 AM, Daniel Vetter  wrote:
> On Wed, Mar 25, 2015 at 01:47:54PM +0530, Archit Taneja wrote:
>> Hi,
>>
>> On 03/13/2015 02:36 PM, Daniel Vetter wrote:
>> >On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:
>> >>
>> >>
>> >>On 03/11/2015 08:47 PM, Daniel Vetter wrote:
>> >>>On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:
>> 
>> 
>> On 03/10/2015 05:47 PM, Daniel Vetter wrote:
>> >On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:
>> >>On 03/10/2015 03:35 PM, Daniel Vetter wrote:
>> >>>On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
>> On 03/10/2015 03:17 PM, Daniel Vetter wrote:
>> >On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
>> >>diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
>> >>index 151a050..38f83a0 100644
>> >>--- a/drivers/gpu/drm/Kconfig
>> >>+++ b/drivers/gpu/drm/Kconfig
>> >>@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
>> >>help
>> >>  FBDEV helpers for KMS drivers.
>> >>
>> >>+config DRM_FBDEV_EMULATION
>> >>+   bool "Enable legacy fbdev support for your modesetting driver"
>> >>+   depends on DRM
>> >>+   select DRM_KMS_HELPER
>> >>+   select DRM_KMS_FB_HELPER
>> >>+   select FB_SYS_FILLRECT
>> >>+   select FB_SYS_COPYAREA
>> >>+   select FB_SYS_IMAGEBLIT
>> >>+   select FB_SYS_FOPS
>> >>+   select FB_CFB_FILLRECT
>> >>+   select FB_CFB_COPYAREA
>> >>+   select FB_CFB_IMAGEBLIT
>> >>+   default y
>> >>+   help
>> >>+ Choose this option if you have a need for the legacy fbdev
>> >>+ support. Note that this support also provide the linux 
>> >>console
>> >>+ support on top of your modesetting driver.
>> >
>> >Maybe clarify that for linux console support you also need
>> >CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
>> 
>> DRM_KMS_FB_HELPER selects that for us, right?
>> >>>
>> >>>Hm right I've missed that. Reminds me that you need one more patch at 
>> >>>the
>> >>>end to remove all the various select DRM_KMS_FB_HELPER from all drm
>> >>>drivers. Otherwise this knob here won't work by default if you e.g. 
>> >>>select
>> >>>radeon. In general we can't mix explicit options with menu entries 
>> >>>with a
>> >>>select.
>> >>
>> >>I was trying that out. Removing DRM_KMS_FB_HELPER and having
>> >>DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff 
>> >>internally in
>> >>their respective xyz_fbdev.c files.
>> >
>> >But with the stubbed out functions that should work, right? Why doesn't
>> >it?
>> 
>> There are still calls to functions from fb core like fb_set_suspend and
>> register_framebuffer which aren't covered by the drm fb helper functions.
>> >>>
>> >>>Hm, sounds like we need another patch to stub out fb_set_suspend when
>> >>>fbdev isn't enabled. Is there anything else?
>> >>
>> >>There are a handful of fb core functions which are called by drm drivers:
>> >>
>> >>fb_alloc_cmap/fb_dealloc_cmap
>> >>
>> >>fb_sys_read/fb_sys_write
>> >>
>> >>register_framebuffer/unregister_framebuffer/unlink_framebuffer/
>> >>remove_conflicting_framebuffers
>> >>
>> >>fb_set_suspend
>> >>
>> >>fb_deferred_io_init/fb_deferred_io_cleanup
>> >>
>> >>framebuffer_alloc/framebuffer_release
>> >
>> >Hm yeah that's somewhat annoying indeed. What about the following:
>> >1. We move all the #include  from drivers into drm_fb_helper.h
>> >
>> >2. Then we add stubs for these functions in drm_fb_helper.h, like this
>> >
>> >#if defined(CONFIG_FB)
>> >#include 
>> >#else
>> >
>> >/* static inline stubs for all the fb stuff used by kms drivers */
>> >#endif
>> >
>> >Imo this makes sense since kms drivers really have a bit a special
>> >situation with fbdev. They're not full-blown fbdev drivers and can be
>> >useful fully without fbdev.
>> >
>>
>> I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs
>> won't really work because struct declarations(like fb_info) also get
>> removed.
>>
>> I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h itself,
>> but that seemed a bit too intrusive.
>>
>> This is what I'm currently doing:
>>
>> - Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap would
>> actually benefit if we have drm fb helpers for them. They are used in
>> exactly the same manner by all the drivers.
>>
>> - For the rest of the functions that are sparsely used, I was considering
>> making very simple drm_fb_* wrapper functions. Something like:
>>
>> void 

Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-06-30 Thread Benjamin Gaignard
Hi,

I think that what have been done by Rob with module_param is also a good idea:
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/gpu/drm/msm/msm_drv.c?id=e90dfec78ec288d6c89a7b508a5c5d4ae8b7f934

Can you mix compilation flag and module param ?

Benjamin

2015-06-30 9:56 GMT+02:00 Archit Taneja arch...@codeaurora.org:
 Hi,

 On 06/30/2015 12:40 PM, Daniel Vetter wrote:

 Any updates on this or too much distractions? I really think doing
 this would be awesome for the drm subsystem, instead of reinventing
 this wheel for each driver.


 I'd started on this again. I've got more free time now than before, so I
 should have something in a week or so. I agree it will help a lot (there are
 already two new drivers since we started discussing this!)

 Archit


 -Daniel

 On Wed, Mar 25, 2015 at 10:21 AM, Daniel Vetter dan...@ffwll.ch wrote:

 On Wed, Mar 25, 2015 at 01:47:54PM +0530, Archit Taneja wrote:

 Hi,

 On 03/13/2015 02:36 PM, Daniel Vetter wrote:

 On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:



 On 03/11/2015 08:47 PM, Daniel Vetter wrote:

 On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:



 On 03/10/2015 05:47 PM, Daniel Vetter wrote:

 On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:

 On 03/10/2015 03:35 PM, Daniel Vetter wrote:

 On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:

 On 03/10/2015 03:17 PM, Daniel Vetter wrote:

 On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

 diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
 index 151a050..38f83a0 100644
 --- a/drivers/gpu/drm/Kconfig
 +++ b/drivers/gpu/drm/Kconfig
 @@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
 help
   FBDEV helpers for KMS drivers.

 +config DRM_FBDEV_EMULATION
 +   bool Enable legacy fbdev support for your modesetting
 driver
 +   depends on DRM
 +   select DRM_KMS_HELPER
 +   select DRM_KMS_FB_HELPER
 +   select FB_SYS_FILLRECT
 +   select FB_SYS_COPYAREA
 +   select FB_SYS_IMAGEBLIT
 +   select FB_SYS_FOPS
 +   select FB_CFB_FILLRECT
 +   select FB_CFB_COPYAREA
 +   select FB_CFB_IMAGEBLIT
 +   default y
 +   help
 + Choose this option if you have a need for the legacy
 fbdev
 + support. Note that this support also provide the linux
 console
 + support on top of your modesetting driver.


 Maybe clarify that for linux console support you also need
 CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.


 DRM_KMS_FB_HELPER selects that for us, right?


 Hm right I've missed that. Reminds me that you need one more
 patch at the
 end to remove all the various select DRM_KMS_FB_HELPER from all
 drm
 drivers. Otherwise this knob here won't work by default if you
 e.g. select
 radeon. In general we can't mix explicit options with menu
 entries with a
 select.


 I was trying that out. Removing DRM_KMS_FB_HELPER and having
 DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff
 internally in
 their respective xyz_fbdev.c files.


 But with the stubbed out functions that should work, right? Why
 doesn't
 it?


 There are still calls to functions from fb core like fb_set_suspend
 and
 register_framebuffer which aren't covered by the drm fb helper
 functions.


 Hm, sounds like we need another patch to stub out fb_set_suspend when
 fbdev isn't enabled. Is there anything else?


 There are a handful of fb core functions which are called by drm
 drivers:

 fb_alloc_cmap/fb_dealloc_cmap

 fb_sys_read/fb_sys_write

 register_framebuffer/unregister_framebuffer/unlink_framebuffer/
 remove_conflicting_framebuffers

 fb_set_suspend

 fb_deferred_io_init/fb_deferred_io_cleanup

 framebuffer_alloc/framebuffer_release


 Hm yeah that's somewhat annoying indeed. What about the following:
 1. We move all the #include linux/fb.h from drivers into
 drm_fb_helper.h

 2. Then we add stubs for these functions in drm_fb_helper.h, like this

 #if defined(CONFIG_FB)
 #include linux/fb.h
 #else

 /* static inline stubs for all the fb stuff used by kms drivers */
 #endif

 Imo this makes sense since kms drivers really have a bit a special
 situation with fbdev. They're not full-blown fbdev drivers and can be
 useful fully without fbdev.


 I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs
 won't really work because struct declarations(like fb_info) also get
 removed.

 I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h
 itself,
 but that seemed a bit too intrusive.

 This is what I'm currently doing:

 - Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap
 would
 actually benefit if we have drm fb helpers for them. They are used in
 exactly the same manner by all the drivers.

 - For the rest of the functions that are sparsely used, I was
 considering
 making very simple drm_fb_* wrapper functions. Something like:

 void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)
 {
if (helper-fbdev)

Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-06-30 Thread Archit Taneja

Hi,

On 06/30/2015 02:01 PM, Benjamin Gaignard wrote:

Hi,

I think that what have been done by Rob with module_param is also a good idea:
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/gpu/drm/msm/msm_drv.c?id=e90dfec78ec288d6c89a7b508a5c5d4ae8b7f934

Can you mix compilation flag and module param ?


I guess this won't be hard to do once we have a common fbdev emulation 
config option. We could consider this as a drm top level module param.


I'll keep this in mind.

Thanks,
Archit



Benjamin

2015-06-30 9:56 GMT+02:00 Archit Taneja arch...@codeaurora.org:

Hi,

On 06/30/2015 12:40 PM, Daniel Vetter wrote:


Any updates on this or too much distractions? I really think doing
this would be awesome for the drm subsystem, instead of reinventing
this wheel for each driver.



I'd started on this again. I've got more free time now than before, so I
should have something in a week or so. I agree it will help a lot (there are
already two new drivers since we started discussing this!)

Archit



-Daniel

On Wed, Mar 25, 2015 at 10:21 AM, Daniel Vetter dan...@ffwll.ch wrote:


On Wed, Mar 25, 2015 at 01:47:54PM +0530, Archit Taneja wrote:


Hi,

On 03/13/2015 02:36 PM, Daniel Vetter wrote:


On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:




On 03/11/2015 08:47 PM, Daniel Vetter wrote:


On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:




On 03/10/2015 05:47 PM, Daniel Vetter wrote:


On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:


On 03/10/2015 03:35 PM, Daniel Vetter wrote:


On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:


On 03/10/2015 03:17 PM, Daniel Vetter wrote:


On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:


diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
 help
   FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool Enable legacy fbdev support for your modesetting
driver
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy
fbdev
+ support. Note that this support also provide the linux
console
+ support on top of your modesetting driver.



Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.



DRM_KMS_FB_HELPER selects that for us, right?



Hm right I've missed that. Reminds me that you need one more
patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all
drm
drivers. Otherwise this knob here won't work by default if you
e.g. select
radeon. In general we can't mix explicit options with menu
entries with a
select.



I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff
internally in
their respective xyz_fbdev.c files.



But with the stubbed out functions that should work, right? Why
doesn't
it?



There are still calls to functions from fb core like fb_set_suspend
and
register_framebuffer which aren't covered by the drm fb helper
functions.



Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?



There are a handful of fb core functions which are called by drm
drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release



Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include linux/fb.h from drivers into
drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include linux/fb.h
#else

/* static inline stubs for all the fb stuff used by kms drivers */
#endif

Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.



I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs
won't really work because struct declarations(like fb_info) also get
removed.

I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h
itself,
but that seemed a bit too intrusive.

This is what I'm currently doing:

- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap
would
actually benefit if we have drm fb helpers for them. They are used in
exactly the same manner by all the drivers.

- For the rest of the functions that are sparsely used, I was
considering
making very simple drm_fb_* wrapper 

Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-06-30 Thread Archit Taneja

Hi,

On 06/30/2015 12:40 PM, Daniel Vetter wrote:

Any updates on this or too much distractions? I really think doing
this would be awesome for the drm subsystem, instead of reinventing
this wheel for each driver.


I'd started on this again. I've got more free time now than before, so I 
should have something in a week or so. I agree it will help a lot (there 
are already two new drivers since we started discussing this!)


Archit


-Daniel

On Wed, Mar 25, 2015 at 10:21 AM, Daniel Vetter dan...@ffwll.ch wrote:

On Wed, Mar 25, 2015 at 01:47:54PM +0530, Archit Taneja wrote:

Hi,

On 03/13/2015 02:36 PM, Daniel Vetter wrote:

On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:



On 03/11/2015 08:47 PM, Daniel Vetter wrote:

On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:



On 03/10/2015 05:47 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:

On 03/10/2015 03:35 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:

On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
  FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool Enable legacy fbdev support for your modesetting driver
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.


Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.


DRM_KMS_FB_HELPER selects that for us, right?


Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.


I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.


But with the stubbed out functions that should work, right? Why doesn't
it?


There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.


Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?


There are a handful of fb core functions which are called by drm drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release


Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include linux/fb.h from drivers into drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include linux/fb.h
#else

/* static inline stubs for all the fb stuff used by kms drivers */
#endif

Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.



I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs
won't really work because struct declarations(like fb_info) also get
removed.

I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h itself,
but that seemed a bit too intrusive.

This is what I'm currently doing:

- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap would
actually benefit if we have drm fb helpers for them. They are used in
exactly the same manner by all the drivers.

- For the rest of the functions that are sparsely used, I was considering
making very simple drm_fb_* wrapper functions. Something like:

void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)
{
   if (helper-fbdev)
   fb_deferred_io_init(helper-fbdev);
}

We could have all fb calls called within drm_fb_helper.c, creating
drm_fb_helper_* stub functions would then be an easier task. What do you
think?


That's actually an option I considered, but I hoped we could do it with
less work. If this indeed works and you can create the patch that would be
awesome.

Thanks, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch






--
Qualcomm Innovation Center, Inc. is a member of Code 

Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-06-30 Thread Daniel Vetter
On Tue, Jun 30, 2015 at 10:31 AM, Benjamin Gaignard
benjamin.gaign...@linaro.org wrote:
 I think that what have been done by Rob with module_param is also a good idea:
 https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/gpu/drm/msm/msm_drv.c?id=e90dfec78ec288d6c89a7b508a5c5d4ae8b7f934

 Can you mix compilation flag and module param ?

Hm, the point of the kconfig is to not require all the legacy baggage
from fbdev. But I guess a module option could be added later on too.
bochs has it too.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/


Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-06-30 Thread Daniel Vetter
Any updates on this or too much distractions? I really think doing
this would be awesome for the drm subsystem, instead of reinventing
this wheel for each driver.
-Daniel

On Wed, Mar 25, 2015 at 10:21 AM, Daniel Vetter dan...@ffwll.ch wrote:
 On Wed, Mar 25, 2015 at 01:47:54PM +0530, Archit Taneja wrote:
 Hi,

 On 03/13/2015 02:36 PM, Daniel Vetter wrote:
 On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:
 
 
 On 03/11/2015 08:47 PM, Daniel Vetter wrote:
 On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:
 
 
 On 03/10/2015 05:47 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:
 On 03/10/2015 03:35 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
 On 03/10/2015 03:17 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
 diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
 index 151a050..38f83a0 100644
 --- a/drivers/gpu/drm/Kconfig
 +++ b/drivers/gpu/drm/Kconfig
 @@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
 help
   FBDEV helpers for KMS drivers.
 
 +config DRM_FBDEV_EMULATION
 +   bool Enable legacy fbdev support for your modesetting driver
 +   depends on DRM
 +   select DRM_KMS_HELPER
 +   select DRM_KMS_FB_HELPER
 +   select FB_SYS_FILLRECT
 +   select FB_SYS_COPYAREA
 +   select FB_SYS_IMAGEBLIT
 +   select FB_SYS_FOPS
 +   select FB_CFB_FILLRECT
 +   select FB_CFB_COPYAREA
 +   select FB_CFB_IMAGEBLIT
 +   default y
 +   help
 + Choose this option if you have a need for the legacy fbdev
 + support. Note that this support also provide the linux 
 console
 + support on top of your modesetting driver.
 
 Maybe clarify that for linux console support you also need
 CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
 
 DRM_KMS_FB_HELPER selects that for us, right?
 
 Hm right I've missed that. Reminds me that you need one more patch at 
 the
 end to remove all the various select DRM_KMS_FB_HELPER from all drm
 drivers. Otherwise this knob here won't work by default if you e.g. 
 select
 radeon. In general we can't mix explicit options with menu entries 
 with a
 select.
 
 I was trying that out. Removing DRM_KMS_FB_HELPER and having
 DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff 
 internally in
 their respective xyz_fbdev.c files.
 
 But with the stubbed out functions that should work, right? Why doesn't
 it?
 
 There are still calls to functions from fb core like fb_set_suspend and
 register_framebuffer which aren't covered by the drm fb helper functions.
 
 Hm, sounds like we need another patch to stub out fb_set_suspend when
 fbdev isn't enabled. Is there anything else?
 
 There are a handful of fb core functions which are called by drm drivers:
 
 fb_alloc_cmap/fb_dealloc_cmap
 
 fb_sys_read/fb_sys_write
 
 register_framebuffer/unregister_framebuffer/unlink_framebuffer/
 remove_conflicting_framebuffers
 
 fb_set_suspend
 
 fb_deferred_io_init/fb_deferred_io_cleanup
 
 framebuffer_alloc/framebuffer_release
 
 Hm yeah that's somewhat annoying indeed. What about the following:
 1. We move all the #include linux/fb.h from drivers into drm_fb_helper.h
 
 2. Then we add stubs for these functions in drm_fb_helper.h, like this
 
 #if defined(CONFIG_FB)
 #include linux/fb.h
 #else
 
 /* static inline stubs for all the fb stuff used by kms drivers */
 #endif
 
 Imo this makes sense since kms drivers really have a bit a special
 situation with fbdev. They're not full-blown fbdev drivers and can be
 useful fully without fbdev.
 

 I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs
 won't really work because struct declarations(like fb_info) also get
 removed.

 I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h itself,
 but that seemed a bit too intrusive.

 This is what I'm currently doing:

 - Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap would
 actually benefit if we have drm fb helpers for them. They are used in
 exactly the same manner by all the drivers.

 - For the rest of the functions that are sparsely used, I was considering
 making very simple drm_fb_* wrapper functions. Something like:

 void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)
 {
   if (helper-fbdev)
   fb_deferred_io_init(helper-fbdev);
 }

 We could have all fb calls called within drm_fb_helper.c, creating
 drm_fb_helper_* stub functions would then be an easier task. What do you
 think?

 That's actually an option I considered, but I hoped we could do it with
 less work. If this indeed works and you can create the patch that would be
 awesome.

 Thanks, Daniel
 --
 Daniel Vetter
 Software Engineer, Intel Corporation
 http://blog.ffwll.ch



-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org

Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-25 Thread Daniel Vetter
On Wed, Mar 25, 2015 at 01:47:54PM +0530, Archit Taneja wrote:
> Hi,
> 
> On 03/13/2015 02:36 PM, Daniel Vetter wrote:
> >On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:
> >>
> >>
> >>On 03/11/2015 08:47 PM, Daniel Vetter wrote:
> >>>On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:
> 
> 
> On 03/10/2015 05:47 PM, Daniel Vetter wrote:
> >On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:
> >>On 03/10/2015 03:35 PM, Daniel Vetter wrote:
> >>>On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
> On 03/10/2015 03:17 PM, Daniel Vetter wrote:
> >On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
> >>diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> >>index 151a050..38f83a0 100644
> >>--- a/drivers/gpu/drm/Kconfig
> >>+++ b/drivers/gpu/drm/Kconfig
> >>@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
> >>help
> >>  FBDEV helpers for KMS drivers.
> >>
> >>+config DRM_FBDEV_EMULATION
> >>+   bool "Enable legacy fbdev support for your modesetting driver"
> >>+   depends on DRM
> >>+   select DRM_KMS_HELPER
> >>+   select DRM_KMS_FB_HELPER
> >>+   select FB_SYS_FILLRECT
> >>+   select FB_SYS_COPYAREA
> >>+   select FB_SYS_IMAGEBLIT
> >>+   select FB_SYS_FOPS
> >>+   select FB_CFB_FILLRECT
> >>+   select FB_CFB_COPYAREA
> >>+   select FB_CFB_IMAGEBLIT
> >>+   default y
> >>+   help
> >>+ Choose this option if you have a need for the legacy fbdev
> >>+ support. Note that this support also provide the linux console
> >>+ support on top of your modesetting driver.
> >
> >Maybe clarify that for linux console support you also need
> >CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
> 
> DRM_KMS_FB_HELPER selects that for us, right?
> >>>
> >>>Hm right I've missed that. Reminds me that you need one more patch at 
> >>>the
> >>>end to remove all the various select DRM_KMS_FB_HELPER from all drm
> >>>drivers. Otherwise this knob here won't work by default if you e.g. 
> >>>select
> >>>radeon. In general we can't mix explicit options with menu entries 
> >>>with a
> >>>select.
> >>
> >>I was trying that out. Removing DRM_KMS_FB_HELPER and having
> >>DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff 
> >>internally in
> >>their respective xyz_fbdev.c files.
> >
> >But with the stubbed out functions that should work, right? Why doesn't
> >it?
> 
> There are still calls to functions from fb core like fb_set_suspend and
> register_framebuffer which aren't covered by the drm fb helper functions.
> >>>
> >>>Hm, sounds like we need another patch to stub out fb_set_suspend when
> >>>fbdev isn't enabled. Is there anything else?
> >>
> >>There are a handful of fb core functions which are called by drm drivers:
> >>
> >>fb_alloc_cmap/fb_dealloc_cmap
> >>
> >>fb_sys_read/fb_sys_write
> >>
> >>register_framebuffer/unregister_framebuffer/unlink_framebuffer/
> >>remove_conflicting_framebuffers
> >>
> >>fb_set_suspend
> >>
> >>fb_deferred_io_init/fb_deferred_io_cleanup
> >>
> >>framebuffer_alloc/framebuffer_release
> >
> >Hm yeah that's somewhat annoying indeed. What about the following:
> >1. We move all the #include  from drivers into drm_fb_helper.h
> >
> >2. Then we add stubs for these functions in drm_fb_helper.h, like this
> >
> >#if defined(CONFIG_FB)
> >#include 
> >#else
> >
> >/* static inline stubs for all the fb stuff used by kms drivers */
> >#endif
> >
> >Imo this makes sense since kms drivers really have a bit a special
> >situation with fbdev. They're not full-blown fbdev drivers and can be
> >useful fully without fbdev.
> >
> 
> I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs
> won't really work because struct declarations(like fb_info) also get
> removed.
> 
> I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h itself,
> but that seemed a bit too intrusive.
> 
> This is what I'm currently doing:
> 
> - Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap would
> actually benefit if we have drm fb helpers for them. They are used in
> exactly the same manner by all the drivers.
> 
> - For the rest of the functions that are sparsely used, I was considering
> making very simple drm_fb_* wrapper functions. Something like:
> 
> void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)
> {
>   if (helper->fbdev)
>   fb_deferred_io_init(helper->fbdev);
> }
> 
> We could have all fb calls called within drm_fb_helper.c, creating
> drm_fb_helper_* stub functions would then be an easier task. What do you
> think?

That's actually an option I considered, but I hoped we could do it with
less work. 

Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-25 Thread Archit Taneja

Hi,

On 03/13/2015 02:36 PM, Daniel Vetter wrote:

On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:



On 03/11/2015 08:47 PM, Daniel Vetter wrote:

On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:



On 03/10/2015 05:47 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:

On 03/10/2015 03:35 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:

On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
  FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool "Enable legacy fbdev support for your modesetting driver"
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.


Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.


DRM_KMS_FB_HELPER selects that for us, right?


Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.


I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.


But with the stubbed out functions that should work, right? Why doesn't
it?


There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.


Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?


There are a handful of fb core functions which are called by drm drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release


Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include  from drivers into drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include 
#else

/* static inline stubs for all the fb stuff used by kms drivers */
#endif

Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.



I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs 
won't really work because struct declarations(like fb_info) also get 
removed.


I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h 
itself, but that seemed a bit too intrusive.


This is what I'm currently doing:

- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap 
would actually benefit if we have drm fb helpers for them. They are used 
in exactly the same manner by all the drivers.


- For the rest of the functions that are sparsely used, I was 
considering making very simple drm_fb_* wrapper functions. Something like:


void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)
{
if (helper->fbdev)
fb_deferred_io_init(helper->fbdev);
}

We could have all fb calls called within drm_fb_helper.c, creating 
drm_fb_helper_* stub functions would then be an easier task. What do you 
think?


Archit

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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-25 Thread Archit Taneja

Hi,

On 03/13/2015 02:36 PM, Daniel Vetter wrote:

On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:



On 03/11/2015 08:47 PM, Daniel Vetter wrote:

On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:



On 03/10/2015 05:47 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:

On 03/10/2015 03:35 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:

On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
  FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool Enable legacy fbdev support for your modesetting driver
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.


Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.


DRM_KMS_FB_HELPER selects that for us, right?


Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.


I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.


But with the stubbed out functions that should work, right? Why doesn't
it?


There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.


Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?


There are a handful of fb core functions which are called by drm drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release


Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include linux/fb.h from drivers into drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include linux/fb.h
#else

/* static inline stubs for all the fb stuff used by kms drivers */
#endif

Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.



I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs 
won't really work because struct declarations(like fb_info) also get 
removed.


I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h 
itself, but that seemed a bit too intrusive.


This is what I'm currently doing:

- Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap 
would actually benefit if we have drm fb helpers for them. They are used 
in exactly the same manner by all the drivers.


- For the rest of the functions that are sparsely used, I was 
considering making very simple drm_fb_* wrapper functions. Something like:


void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)
{
if (helper-fbdev)
fb_deferred_io_init(helper-fbdev);
}

We could have all fb calls called within drm_fb_helper.c, creating 
drm_fb_helper_* stub functions would then be an easier task. What do you 
think?


Archit

--
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--
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Please read the FAQ at  http://www.tux.org/lkml/


Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-25 Thread Daniel Vetter
On Wed, Mar 25, 2015 at 01:47:54PM +0530, Archit Taneja wrote:
 Hi,
 
 On 03/13/2015 02:36 PM, Daniel Vetter wrote:
 On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:
 
 
 On 03/11/2015 08:47 PM, Daniel Vetter wrote:
 On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:
 
 
 On 03/10/2015 05:47 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:
 On 03/10/2015 03:35 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
 On 03/10/2015 03:17 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
 diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
 index 151a050..38f83a0 100644
 --- a/drivers/gpu/drm/Kconfig
 +++ b/drivers/gpu/drm/Kconfig
 @@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
 help
   FBDEV helpers for KMS drivers.
 
 +config DRM_FBDEV_EMULATION
 +   bool Enable legacy fbdev support for your modesetting driver
 +   depends on DRM
 +   select DRM_KMS_HELPER
 +   select DRM_KMS_FB_HELPER
 +   select FB_SYS_FILLRECT
 +   select FB_SYS_COPYAREA
 +   select FB_SYS_IMAGEBLIT
 +   select FB_SYS_FOPS
 +   select FB_CFB_FILLRECT
 +   select FB_CFB_COPYAREA
 +   select FB_CFB_IMAGEBLIT
 +   default y
 +   help
 + Choose this option if you have a need for the legacy fbdev
 + support. Note that this support also provide the linux console
 + support on top of your modesetting driver.
 
 Maybe clarify that for linux console support you also need
 CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
 
 DRM_KMS_FB_HELPER selects that for us, right?
 
 Hm right I've missed that. Reminds me that you need one more patch at 
 the
 end to remove all the various select DRM_KMS_FB_HELPER from all drm
 drivers. Otherwise this knob here won't work by default if you e.g. 
 select
 radeon. In general we can't mix explicit options with menu entries 
 with a
 select.
 
 I was trying that out. Removing DRM_KMS_FB_HELPER and having
 DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff 
 internally in
 their respective xyz_fbdev.c files.
 
 But with the stubbed out functions that should work, right? Why doesn't
 it?
 
 There are still calls to functions from fb core like fb_set_suspend and
 register_framebuffer which aren't covered by the drm fb helper functions.
 
 Hm, sounds like we need another patch to stub out fb_set_suspend when
 fbdev isn't enabled. Is there anything else?
 
 There are a handful of fb core functions which are called by drm drivers:
 
 fb_alloc_cmap/fb_dealloc_cmap
 
 fb_sys_read/fb_sys_write
 
 register_framebuffer/unregister_framebuffer/unlink_framebuffer/
 remove_conflicting_framebuffers
 
 fb_set_suspend
 
 fb_deferred_io_init/fb_deferred_io_cleanup
 
 framebuffer_alloc/framebuffer_release
 
 Hm yeah that's somewhat annoying indeed. What about the following:
 1. We move all the #include linux/fb.h from drivers into drm_fb_helper.h
 
 2. Then we add stubs for these functions in drm_fb_helper.h, like this
 
 #if defined(CONFIG_FB)
 #include linux/fb.h
 #else
 
 /* static inline stubs for all the fb stuff used by kms drivers */
 #endif
 
 Imo this makes sense since kms drivers really have a bit a special
 situation with fbdev. They're not full-blown fbdev drivers and can be
 useful fully without fbdev.
 
 
 I was trying this out. Removing 'linux/fb.h' and replacing stub fb funcs
 won't really work because struct declarations(like fb_info) also get
 removed.
 
 I considered placing '#if IS_ENABLED(CONFIG_FB)' within linux/fb.h itself,
 but that seemed a bit too intrusive.
 
 This is what I'm currently doing:
 
 - Some funcs, like framebufer_alloc/release, alloc_cmap/dealloc_cmap would
 actually benefit if we have drm fb helpers for them. They are used in
 exactly the same manner by all the drivers.
 
 - For the rest of the functions that are sparsely used, I was considering
 making very simple drm_fb_* wrapper functions. Something like:
 
 void drm_fb_helper_deferred_io_init(struct drm_fb_helper *helper)
 {
   if (helper-fbdev)
   fb_deferred_io_init(helper-fbdev);
 }
 
 We could have all fb calls called within drm_fb_helper.c, creating
 drm_fb_helper_* stub functions would then be an easier task. What do you
 think?

That's actually an option I considered, but I hoped we could do it with
less work. If this indeed works and you can create the patch that would be
awesome.

Thanks, Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-13 Thread Archit Taneja



On 03/13/2015 02:36 PM, Daniel Vetter wrote:

On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:



On 03/11/2015 08:47 PM, Daniel Vetter wrote:

On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:



On 03/10/2015 05:47 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:

On 03/10/2015 03:35 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:

On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
  FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool "Enable legacy fbdev support for your modesetting driver"
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.


Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.


DRM_KMS_FB_HELPER selects that for us, right?


Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.


I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.


But with the stubbed out functions that should work, right? Why doesn't
it?


There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.


Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?


There are a handful of fb core functions which are called by drm drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release


Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include  from drivers into drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include 
#else

/* static inline stubs for all the fb stuff used by kms drivers */
#endif

Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.

What do you think?


This looks good! I'll give it a try.

Archit

--
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a Linux Foundation Collaborative Project
--
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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-13 Thread Jani Nikula
On Fri, 13 Mar 2015, Daniel Vetter  wrote:
> #if defined(CONFIG_FB)
> #include 
> #else

Side note, #if IS_ENABLED(CONFIG_FB)

BR,
Jani.


-- 
Jani Nikula, Intel Open Source Technology Center
--
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Please read the FAQ at  http://www.tux.org/lkml/


Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-13 Thread Daniel Vetter
On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:
> 
> 
> On 03/11/2015 08:47 PM, Daniel Vetter wrote:
> >On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:
> >>
> >>
> >>On 03/10/2015 05:47 PM, Daniel Vetter wrote:
> >>>On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:
> On 03/10/2015 03:35 PM, Daniel Vetter wrote:
> >On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
> >>On 03/10/2015 03:17 PM, Daniel Vetter wrote:
> >>>On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 151a050..38f83a0 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
>   help
> FBDEV helpers for KMS drivers.
> 
> +config DRM_FBDEV_EMULATION
> + bool "Enable legacy fbdev support for your modesetting driver"
> + depends on DRM
> + select DRM_KMS_HELPER
> + select DRM_KMS_FB_HELPER
> + select FB_SYS_FILLRECT
> + select FB_SYS_COPYAREA
> + select FB_SYS_IMAGEBLIT
> + select FB_SYS_FOPS
> + select FB_CFB_FILLRECT
> + select FB_CFB_COPYAREA
> + select FB_CFB_IMAGEBLIT
> + default y
> + help
> +   Choose this option if you have a need for the legacy fbdev
> +   support. Note that this support also provide the linux console
> +   support on top of your modesetting driver.
> >>>
> >>>Maybe clarify that for linux console support you also need
> >>>CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
> >>
> >>DRM_KMS_FB_HELPER selects that for us, right?
> >
> >Hm right I've missed that. Reminds me that you need one more patch at the
> >end to remove all the various select DRM_KMS_FB_HELPER from all drm
> >drivers. Otherwise this knob here won't work by default if you e.g. 
> >select
> >radeon. In general we can't mix explicit options with menu entries with a
> >select.
> 
> I was trying that out. Removing DRM_KMS_FB_HELPER and having
> DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally 
> in
> their respective xyz_fbdev.c files.
> >>>
> >>>But with the stubbed out functions that should work, right? Why doesn't
> >>>it?
> >>
> >>There are still calls to functions from fb core like fb_set_suspend and
> >>register_framebuffer which aren't covered by the drm fb helper functions.
> >
> >Hm, sounds like we need another patch to stub out fb_set_suspend when
> >fbdev isn't enabled. Is there anything else?
> 
> There are a handful of fb core functions which are called by drm drivers:
> 
> fb_alloc_cmap/fb_dealloc_cmap
> 
> fb_sys_read/fb_sys_write
> 
> register_framebuffer/unregister_framebuffer/unlink_framebuffer/
> remove_conflicting_framebuffers
> 
> fb_set_suspend
> 
> fb_deferred_io_init/fb_deferred_io_cleanup
> 
> framebuffer_alloc/framebuffer_release

Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include  from drivers into drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include 
#else

/* static inline stubs for all the fb stuff used by kms drivers */
#endif

Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.

What do you think?
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-13 Thread Archit Taneja



On 03/11/2015 08:47 PM, Daniel Vetter wrote:

On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:



On 03/10/2015 05:47 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:

On 03/10/2015 03:35 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:

On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
  FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool "Enable legacy fbdev support for your modesetting driver"
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.


Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.


DRM_KMS_FB_HELPER selects that for us, right?


Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.


I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.


But with the stubbed out functions that should work, right? Why doesn't
it?


There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.


Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?


There are a handful of fb core functions which are called by drm drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release





Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers and
replace them with 'select DRM_FBDEV_EMULATION'?

Another option would be to provide #ifdef DRM_FBDEV_EMULATION wrap-arounds
for fb related function calls/declarations in each driver, something that's
already done for i915 and msm drivers.


The problem with the patch as-is the massive amounts of selects the FB
helper still has. We need to get rid of them so that when you disable
fbdev emulation you can indeed disable fbcon and the entire fbdev
subsystem. I've thought that remove the hidden symbol DRM_KMS_FB_HELPER
and moving all the selects to DRM_FBDEV_EMULATION should work out? If that
doesn't work we need to look again how to better stub things out I think.


That's true. Also, as Jani pointed out, maybe it isn't the best idea to make
every kms driver select DRM_FBDEV_EMULATION?

Maybe the drivers that are currently built with fbdev emulation by default
can add a 'depends on DRM_FBDEV_EMULATION'? Since the config defaults to y,
the drivers should run as is. Later, we could take up each driver and build
the fb stuff only when DRM_FBDEV_EMULATION is set, like how we do for i915
and msm?


Yeah we definitely can't mix select with a user-visible option. I think we
just need to fix up the remaining functions and create stubs for them if
needed and then drop all the selects. Well in DRM_FBDEV_EMULATION we
should still select for fbcon since otherwise tons of bug reports about
"where is my fbcon with kms?".


I'll give this a try. Although, it would be a better idea to make the 
drivers not call these at all when fbdev emulation isn't asked for. With 
the stubs, if someone does try to use the driver with 
DRM_FBDEV_EMULATION not set, the worst that'll happen would be that the 
driver fails to probe. Which isn't so bad.


Archit

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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-13 Thread Archit Taneja



On 03/11/2015 08:47 PM, Daniel Vetter wrote:

On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:



On 03/10/2015 05:47 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:

On 03/10/2015 03:35 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:

On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
  FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool Enable legacy fbdev support for your modesetting driver
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.


Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.


DRM_KMS_FB_HELPER selects that for us, right?


Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.


I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.


But with the stubbed out functions that should work, right? Why doesn't
it?


There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.


Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?


There are a handful of fb core functions which are called by drm drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release





Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers and
replace them with 'select DRM_FBDEV_EMULATION'?

Another option would be to provide #ifdef DRM_FBDEV_EMULATION wrap-arounds
for fb related function calls/declarations in each driver, something that's
already done for i915 and msm drivers.


The problem with the patch as-is the massive amounts of selects the FB
helper still has. We need to get rid of them so that when you disable
fbdev emulation you can indeed disable fbcon and the entire fbdev
subsystem. I've thought that remove the hidden symbol DRM_KMS_FB_HELPER
and moving all the selects to DRM_FBDEV_EMULATION should work out? If that
doesn't work we need to look again how to better stub things out I think.


That's true. Also, as Jani pointed out, maybe it isn't the best idea to make
every kms driver select DRM_FBDEV_EMULATION?

Maybe the drivers that are currently built with fbdev emulation by default
can add a 'depends on DRM_FBDEV_EMULATION'? Since the config defaults to y,
the drivers should run as is. Later, we could take up each driver and build
the fb stuff only when DRM_FBDEV_EMULATION is set, like how we do for i915
and msm?


Yeah we definitely can't mix select with a user-visible option. I think we
just need to fix up the remaining functions and create stubs for them if
needed and then drop all the selects. Well in DRM_FBDEV_EMULATION we
should still select for fbcon since otherwise tons of bug reports about
where is my fbcon with kms?.


I'll give this a try. Although, it would be a better idea to make the 
drivers not call these at all when fbdev emulation isn't asked for. With 
the stubs, if someone does try to use the driver with 
DRM_FBDEV_EMULATION not set, the worst that'll happen would be that the 
driver fails to probe. Which isn't so bad.


Archit

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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-13 Thread Jani Nikula
On Fri, 13 Mar 2015, Daniel Vetter dan...@ffwll.ch wrote:
 #if defined(CONFIG_FB)
 #include linux/fb.h
 #else

Side note, #if IS_ENABLED(CONFIG_FB)

BR,
Jani.


-- 
Jani Nikula, Intel Open Source Technology Center
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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-13 Thread Daniel Vetter
On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:
 
 
 On 03/11/2015 08:47 PM, Daniel Vetter wrote:
 On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:
 
 
 On 03/10/2015 05:47 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:
 On 03/10/2015 03:35 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
 On 03/10/2015 03:17 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
 diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
 index 151a050..38f83a0 100644
 --- a/drivers/gpu/drm/Kconfig
 +++ b/drivers/gpu/drm/Kconfig
 @@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
   help
 FBDEV helpers for KMS drivers.
 
 +config DRM_FBDEV_EMULATION
 + bool Enable legacy fbdev support for your modesetting driver
 + depends on DRM
 + select DRM_KMS_HELPER
 + select DRM_KMS_FB_HELPER
 + select FB_SYS_FILLRECT
 + select FB_SYS_COPYAREA
 + select FB_SYS_IMAGEBLIT
 + select FB_SYS_FOPS
 + select FB_CFB_FILLRECT
 + select FB_CFB_COPYAREA
 + select FB_CFB_IMAGEBLIT
 + default y
 + help
 +   Choose this option if you have a need for the legacy fbdev
 +   support. Note that this support also provide the linux console
 +   support on top of your modesetting driver.
 
 Maybe clarify that for linux console support you also need
 CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
 
 DRM_KMS_FB_HELPER selects that for us, right?
 
 Hm right I've missed that. Reminds me that you need one more patch at the
 end to remove all the various select DRM_KMS_FB_HELPER from all drm
 drivers. Otherwise this knob here won't work by default if you e.g. 
 select
 radeon. In general we can't mix explicit options with menu entries with a
 select.
 
 I was trying that out. Removing DRM_KMS_FB_HELPER and having
 DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally 
 in
 their respective xyz_fbdev.c files.
 
 But with the stubbed out functions that should work, right? Why doesn't
 it?
 
 There are still calls to functions from fb core like fb_set_suspend and
 register_framebuffer which aren't covered by the drm fb helper functions.
 
 Hm, sounds like we need another patch to stub out fb_set_suspend when
 fbdev isn't enabled. Is there anything else?
 
 There are a handful of fb core functions which are called by drm drivers:
 
 fb_alloc_cmap/fb_dealloc_cmap
 
 fb_sys_read/fb_sys_write
 
 register_framebuffer/unregister_framebuffer/unlink_framebuffer/
 remove_conflicting_framebuffers
 
 fb_set_suspend
 
 fb_deferred_io_init/fb_deferred_io_cleanup
 
 framebuffer_alloc/framebuffer_release

Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include linux/fb.h from drivers into drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include linux/fb.h
#else

/* static inline stubs for all the fb stuff used by kms drivers */
#endif

Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.

What do you think?
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
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Please read the FAQ at  http://www.tux.org/lkml/


Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-13 Thread Archit Taneja



On 03/13/2015 02:36 PM, Daniel Vetter wrote:

On Fri, Mar 13, 2015 at 11:55:07AM +0530, Archit Taneja wrote:



On 03/11/2015 08:47 PM, Daniel Vetter wrote:

On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:



On 03/10/2015 05:47 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:

On 03/10/2015 03:35 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:

On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
  FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool Enable legacy fbdev support for your modesetting driver
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.


Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.


DRM_KMS_FB_HELPER selects that for us, right?


Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.


I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.


But with the stubbed out functions that should work, right? Why doesn't
it?


There are still calls to functions from fb core like fb_set_suspend and
register_framebuffer which aren't covered by the drm fb helper functions.


Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?


There are a handful of fb core functions which are called by drm drivers:

fb_alloc_cmap/fb_dealloc_cmap

fb_sys_read/fb_sys_write

register_framebuffer/unregister_framebuffer/unlink_framebuffer/
remove_conflicting_framebuffers

fb_set_suspend

fb_deferred_io_init/fb_deferred_io_cleanup

framebuffer_alloc/framebuffer_release


Hm yeah that's somewhat annoying indeed. What about the following:
1. We move all the #include linux/fb.h from drivers into drm_fb_helper.h

2. Then we add stubs for these functions in drm_fb_helper.h, like this

#if defined(CONFIG_FB)
#include linux/fb.h
#else

/* static inline stubs for all the fb stuff used by kms drivers */
#endif

Imo this makes sense since kms drivers really have a bit a special
situation with fbdev. They're not full-blown fbdev drivers and can be
useful fully without fbdev.

What do you think?


This looks good! I'll give it a try.

Archit

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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-11 Thread Daniel Vetter
On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:
> 
> 
> On 03/10/2015 05:47 PM, Daniel Vetter wrote:
> >On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:
> >>On 03/10/2015 03:35 PM, Daniel Vetter wrote:
> >>>On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
> On 03/10/2015 03:17 PM, Daniel Vetter wrote:
> >On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
> >>diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> >>index 151a050..38f83a0 100644
> >>--- a/drivers/gpu/drm/Kconfig
> >>+++ b/drivers/gpu/drm/Kconfig
> >>@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
> >>help
> >>  FBDEV helpers for KMS drivers.
> >>
> >>+config DRM_FBDEV_EMULATION
> >>+   bool "Enable legacy fbdev support for your modesetting driver"
> >>+   depends on DRM
> >>+   select DRM_KMS_HELPER
> >>+   select DRM_KMS_FB_HELPER
> >>+   select FB_SYS_FILLRECT
> >>+   select FB_SYS_COPYAREA
> >>+   select FB_SYS_IMAGEBLIT
> >>+   select FB_SYS_FOPS
> >>+   select FB_CFB_FILLRECT
> >>+   select FB_CFB_COPYAREA
> >>+   select FB_CFB_IMAGEBLIT
> >>+   default y
> >>+   help
> >>+ Choose this option if you have a need for the legacy fbdev
> >>+ support. Note that this support also provide the linux console
> >>+ support on top of your modesetting driver.
> >
> >Maybe clarify that for linux console support you also need
> >CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
> 
> DRM_KMS_FB_HELPER selects that for us, right?
> >>>
> >>>Hm right I've missed that. Reminds me that you need one more patch at the
> >>>end to remove all the various select DRM_KMS_FB_HELPER from all drm
> >>>drivers. Otherwise this knob here won't work by default if you e.g. select
> >>>radeon. In general we can't mix explicit options with menu entries with a
> >>>select.
> >>
> >>I was trying that out. Removing DRM_KMS_FB_HELPER and having
> >>DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
> >>their respective xyz_fbdev.c files.
> >
> >But with the stubbed out functions that should work, right? Why doesn't
> >it?
> 
> There are still calls to functions from fb core like fb_set_suspend and
> register_framebuffer which aren't covered by the drm fb helper functions.

Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?

> >>Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers and
> >>replace them with 'select DRM_FBDEV_EMULATION'?
> >>
> >>Another option would be to provide #ifdef DRM_FBDEV_EMULATION wrap-arounds
> >>for fb related function calls/declarations in each driver, something that's
> >>already done for i915 and msm drivers.
> >
> >The problem with the patch as-is the massive amounts of selects the FB
> >helper still has. We need to get rid of them so that when you disable
> >fbdev emulation you can indeed disable fbcon and the entire fbdev
> >subsystem. I've thought that remove the hidden symbol DRM_KMS_FB_HELPER
> >and moving all the selects to DRM_FBDEV_EMULATION should work out? If that
> >doesn't work we need to look again how to better stub things out I think.
> 
> That's true. Also, as Jani pointed out, maybe it isn't the best idea to make
> every kms driver select DRM_FBDEV_EMULATION?
> 
> Maybe the drivers that are currently built with fbdev emulation by default
> can add a 'depends on DRM_FBDEV_EMULATION'? Since the config defaults to y,
> the drivers should run as is. Later, we could take up each driver and build
> the fb stuff only when DRM_FBDEV_EMULATION is set, like how we do for i915
> and msm?

Yeah we definitely can't mix select with a user-visible option. I think we
just need to fix up the remaining functions and create stubs for them if
needed and then drop all the selects. Well in DRM_FBDEV_EMULATION we
should still select for fbcon since otherwise tons of bug reports about
"where is my fbcon with kms?".
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
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Please read the FAQ at  http://www.tux.org/lkml/


Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-11 Thread Archit Taneja



On 03/10/2015 05:47 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:

On 03/10/2015 03:35 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:

On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
  FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool "Enable legacy fbdev support for your modesetting driver"
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.


Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.


DRM_KMS_FB_HELPER selects that for us, right?


Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.


I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.


But with the stubbed out functions that should work, right? Why doesn't
it?


There are still calls to functions from fb core like fb_set_suspend and 
register_framebuffer which aren't covered by the drm fb helper functions.





Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers and
replace them with 'select DRM_FBDEV_EMULATION'?

Another option would be to provide #ifdef DRM_FBDEV_EMULATION wrap-arounds
for fb related function calls/declarations in each driver, something that's
already done for i915 and msm drivers.


The problem with the patch as-is the massive amounts of selects the FB
helper still has. We need to get rid of them so that when you disable
fbdev emulation you can indeed disable fbcon and the entire fbdev
subsystem. I've thought that remove the hidden symbol DRM_KMS_FB_HELPER
and moving all the selects to DRM_FBDEV_EMULATION should work out? If that
doesn't work we need to look again how to better stub things out I think.


That's true. Also, as Jani pointed out, maybe it isn't the best idea to 
make every kms driver select DRM_FBDEV_EMULATION?


Maybe the drivers that are currently built with fbdev emulation by 
default can add a 'depends on DRM_FBDEV_EMULATION'? Since the config 
defaults to y, the drivers should run as is. Later, we could take up 
each driver and build the fb stuff only when DRM_FBDEV_EMULATION is set, 
like how we do for i915 and msm?


Archit

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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-11 Thread Daniel Vetter
On Wed, Mar 11, 2015 at 01:51:02PM +0530, Archit Taneja wrote:
 
 
 On 03/10/2015 05:47 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:
 On 03/10/2015 03:35 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
 On 03/10/2015 03:17 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
 diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
 index 151a050..38f83a0 100644
 --- a/drivers/gpu/drm/Kconfig
 +++ b/drivers/gpu/drm/Kconfig
 @@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
 help
   FBDEV helpers for KMS drivers.
 
 +config DRM_FBDEV_EMULATION
 +   bool Enable legacy fbdev support for your modesetting driver
 +   depends on DRM
 +   select DRM_KMS_HELPER
 +   select DRM_KMS_FB_HELPER
 +   select FB_SYS_FILLRECT
 +   select FB_SYS_COPYAREA
 +   select FB_SYS_IMAGEBLIT
 +   select FB_SYS_FOPS
 +   select FB_CFB_FILLRECT
 +   select FB_CFB_COPYAREA
 +   select FB_CFB_IMAGEBLIT
 +   default y
 +   help
 + Choose this option if you have a need for the legacy fbdev
 + support. Note that this support also provide the linux console
 + support on top of your modesetting driver.
 
 Maybe clarify that for linux console support you also need
 CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
 
 DRM_KMS_FB_HELPER selects that for us, right?
 
 Hm right I've missed that. Reminds me that you need one more patch at the
 end to remove all the various select DRM_KMS_FB_HELPER from all drm
 drivers. Otherwise this knob here won't work by default if you e.g. select
 radeon. In general we can't mix explicit options with menu entries with a
 select.
 
 I was trying that out. Removing DRM_KMS_FB_HELPER and having
 DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
 their respective xyz_fbdev.c files.
 
 But with the stubbed out functions that should work, right? Why doesn't
 it?
 
 There are still calls to functions from fb core like fb_set_suspend and
 register_framebuffer which aren't covered by the drm fb helper functions.

Hm, sounds like we need another patch to stub out fb_set_suspend when
fbdev isn't enabled. Is there anything else?

 Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers and
 replace them with 'select DRM_FBDEV_EMULATION'?
 
 Another option would be to provide #ifdef DRM_FBDEV_EMULATION wrap-arounds
 for fb related function calls/declarations in each driver, something that's
 already done for i915 and msm drivers.
 
 The problem with the patch as-is the massive amounts of selects the FB
 helper still has. We need to get rid of them so that when you disable
 fbdev emulation you can indeed disable fbcon and the entire fbdev
 subsystem. I've thought that remove the hidden symbol DRM_KMS_FB_HELPER
 and moving all the selects to DRM_FBDEV_EMULATION should work out? If that
 doesn't work we need to look again how to better stub things out I think.
 
 That's true. Also, as Jani pointed out, maybe it isn't the best idea to make
 every kms driver select DRM_FBDEV_EMULATION?
 
 Maybe the drivers that are currently built with fbdev emulation by default
 can add a 'depends on DRM_FBDEV_EMULATION'? Since the config defaults to y,
 the drivers should run as is. Later, we could take up each driver and build
 the fb stuff only when DRM_FBDEV_EMULATION is set, like how we do for i915
 and msm?

Yeah we definitely can't mix select with a user-visible option. I think we
just need to fix up the remaining functions and create stubs for them if
needed and then drop all the selects. Well in DRM_FBDEV_EMULATION we
should still select for fbcon since otherwise tons of bug reports about
where is my fbcon with kms?.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-11 Thread Archit Taneja



On 03/10/2015 05:47 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:

On 03/10/2015 03:35 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:

On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
  FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool Enable legacy fbdev support for your modesetting driver
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.


Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.


DRM_KMS_FB_HELPER selects that for us, right?


Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.


I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
their respective xyz_fbdev.c files.


But with the stubbed out functions that should work, right? Why doesn't
it?


There are still calls to functions from fb core like fb_set_suspend and 
register_framebuffer which aren't covered by the drm fb helper functions.





Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers and
replace them with 'select DRM_FBDEV_EMULATION'?

Another option would be to provide #ifdef DRM_FBDEV_EMULATION wrap-arounds
for fb related function calls/declarations in each driver, something that's
already done for i915 and msm drivers.


The problem with the patch as-is the massive amounts of selects the FB
helper still has. We need to get rid of them so that when you disable
fbdev emulation you can indeed disable fbcon and the entire fbdev
subsystem. I've thought that remove the hidden symbol DRM_KMS_FB_HELPER
and moving all the selects to DRM_FBDEV_EMULATION should work out? If that
doesn't work we need to look again how to better stub things out I think.


That's true. Also, as Jani pointed out, maybe it isn't the best idea to 
make every kms driver select DRM_FBDEV_EMULATION?


Maybe the drivers that are currently built with fbdev emulation by 
default can add a 'depends on DRM_FBDEV_EMULATION'? Since the config 
defaults to y, the drivers should run as is. Later, we could take up 
each driver and build the fb stuff only when DRM_FBDEV_EMULATION is set, 
like how we do for i915 and msm?


Archit

--
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a Linux Foundation Collaborative Project
--
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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Archit Taneja



On 03/10/2015 09:03 PM, Jani Nikula wrote:

On Tue, 10 Mar 2015, Archit Taneja  wrote:

On 03/10/2015 03:35 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:



On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

DRM_KMS_FB_HELPER selects that for us, right?


Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.


I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff
internally in their respective xyz_fbdev.c files.

Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers
and replace them with 'select DRM_FBDEV_EMULATION'?


Slightly tangential: As a rule of thumb, you should not "select"
anything that is visible in menuconfig or has dependencies [1]. This
will break the build eventually, and attempts to fix it are troublesome
[2].


Thanks, I'll keep this in mind!

Archit

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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Jani Nikula
On Tue, 10 Mar 2015, Archit Taneja  wrote:
> On 03/10/2015 03:35 PM, Daniel Vetter wrote:
>> On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
>>>
>>>
>>> On 03/10/2015 03:17 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
>>> DRM_KMS_FB_HELPER selects that for us, right?
>>
>> Hm right I've missed that. Reminds me that you need one more patch at the
>> end to remove all the various select DRM_KMS_FB_HELPER from all drm
>> drivers. Otherwise this knob here won't work by default if you e.g. select
>> radeon. In general we can't mix explicit options with menu entries with a
>> select.
>
> I was trying that out. Removing DRM_KMS_FB_HELPER and having 
> DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff 
> internally in their respective xyz_fbdev.c files.
>
> Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers 
> and replace them with 'select DRM_FBDEV_EMULATION'?

Slightly tangential: As a rule of thumb, you should not "select"
anything that is visible in menuconfig or has dependencies [1]. This
will break the build eventually, and attempts to fix it are troublesome
[2].

BR,
Jani.

[1] Documentation/kbuild/kconfig-language.txt
[2] http://mid.gmane.org/1413580403-16225-1-git-send-email-jani.nik...@intel.com


-- 
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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Daniel Vetter
On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:
> On 03/10/2015 03:35 PM, Daniel Vetter wrote:
> >On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
> >>On 03/10/2015 03:17 PM, Daniel Vetter wrote:
> >>>On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 151a050..38f83a0 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
>   help
> FBDEV helpers for KMS drivers.
> 
> +config DRM_FBDEV_EMULATION
> + bool "Enable legacy fbdev support for your modesetting driver"
> + depends on DRM
> + select DRM_KMS_HELPER
> + select DRM_KMS_FB_HELPER
> + select FB_SYS_FILLRECT
> + select FB_SYS_COPYAREA
> + select FB_SYS_IMAGEBLIT
> + select FB_SYS_FOPS
> + select FB_CFB_FILLRECT
> + select FB_CFB_COPYAREA
> + select FB_CFB_IMAGEBLIT
> + default y
> + help
> +   Choose this option if you have a need for the legacy fbdev
> +   support. Note that this support also provide the linux console
> +   support on top of your modesetting driver.
> >>>
> >>>Maybe clarify that for linux console support you also need
> >>>CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
> >>
> >>DRM_KMS_FB_HELPER selects that for us, right?
> >
> >Hm right I've missed that. Reminds me that you need one more patch at the
> >end to remove all the various select DRM_KMS_FB_HELPER from all drm
> >drivers. Otherwise this knob here won't work by default if you e.g. select
> >radeon. In general we can't mix explicit options with menu entries with a
> >select.
> 
> I was trying that out. Removing DRM_KMS_FB_HELPER and having
> DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
> their respective xyz_fbdev.c files.

But with the stubbed out functions that should work, right? Why doesn't
it?

> Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers and
> replace them with 'select DRM_FBDEV_EMULATION'?
> 
> Another option would be to provide #ifdef DRM_FBDEV_EMULATION wrap-arounds
> for fb related function calls/declarations in each driver, something that's
> already done for i915 and msm drivers.

The problem with the patch as-is the massive amounts of selects the FB
helper still has. We need to get rid of them so that when you disable
fbdev emulation you can indeed disable fbcon and the entire fbdev
subsystem. I've thought that remove the hidden symbol DRM_KMS_FB_HELPER
and moving all the selects to DRM_FBDEV_EMULATION should work out? If that
doesn't work we need to look again how to better stub things out I think.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
--
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the body of a message to majord...@vger.kernel.org
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Please read the FAQ at  http://www.tux.org/lkml/


Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Archit Taneja



On 03/10/2015 03:35 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:



On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

Legacy fbdev emulation support via DRM is achieved through KMS FB helpers.
Most modesetting drivers enable provide fbdev emulation by default by selecting
KMS FB helpers. A few provide a separate Kconfig option for the user to enable
or disbale fbdev emulation.

Enabling fbdev emulation is finally a distro-level decision. Having a top level
Kconfig option for fbdev emulation helps by providing a uniform way to
enable/disable fbdev emulation for any modesetting driver. It also lets us
remove unnecessary driver specific Kconfig options that causes bloat.

With a top level Kconfig in place, we can stub out the fb helper functions when
not needed without breaking functionality. Having stub functions also prevents
drivers to require wrapping fb helper function calls with #ifdefs.

DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by
default and majority of distributions expect the fbdev interface in the kernel.

For now, this config selects both FB_SYS_* and FB_CFB_* configs as some
modesetting drivers use the former and other the later. This needs to be taken
care of in a better way.

Signed-off-by: Archit Taneja 
---
  drivers/gpu/drm/Kconfig |  18 +++
  drivers/gpu/drm/Makefile|   4 ++
  include/drm/drm_fb_helper.h | 120 
  3 files changed, 142 insertions(+)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
  FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool "Enable legacy fbdev support for your modesetting driver"
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.


Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.


DRM_KMS_FB_HELPER selects that for us, right?


Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.


I was trying that out. Removing DRM_KMS_FB_HELPER and having 
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff 
internally in their respective xyz_fbdev.c files.


Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers 
and replace them with 'select DRM_FBDEV_EMULATION'?


Another option would be to provide #ifdef DRM_FBDEV_EMULATION 
wrap-arounds for fb related function calls/declarations in each driver, 
something that's already done for i915 and msm drivers.


Archit

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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Daniel Vetter
On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
> 
> 
> On 03/10/2015 03:17 PM, Daniel Vetter wrote:
> >On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
> >>Legacy fbdev emulation support via DRM is achieved through KMS FB helpers.
> >>Most modesetting drivers enable provide fbdev emulation by default by 
> >>selecting
> >>KMS FB helpers. A few provide a separate Kconfig option for the user to 
> >>enable
> >>or disbale fbdev emulation.
> >>
> >>Enabling fbdev emulation is finally a distro-level decision. Having a top 
> >>level
> >>Kconfig option for fbdev emulation helps by providing a uniform way to
> >>enable/disable fbdev emulation for any modesetting driver. It also lets us
> >>remove unnecessary driver specific Kconfig options that causes bloat.
> >>
> >>With a top level Kconfig in place, we can stub out the fb helper functions 
> >>when
> >>not needed without breaking functionality. Having stub functions also 
> >>prevents
> >>drivers to require wrapping fb helper function calls with #ifdefs.
> >>
> >>DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation 
> >>by
> >>default and majority of distributions expect the fbdev interface in the 
> >>kernel.
> >>
> >>For now, this config selects both FB_SYS_* and FB_CFB_* configs as some
> >>modesetting drivers use the former and other the later. This needs to be 
> >>taken
> >>care of in a better way.
> >>
> >>Signed-off-by: Archit Taneja 
> >>---
> >>  drivers/gpu/drm/Kconfig |  18 +++
> >>  drivers/gpu/drm/Makefile|   4 ++
> >>  include/drm/drm_fb_helper.h | 120 
> >> 
> >>  3 files changed, 142 insertions(+)
> >>
> >>diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> >>index 151a050..38f83a0 100644
> >>--- a/drivers/gpu/drm/Kconfig
> >>+++ b/drivers/gpu/drm/Kconfig
> >>@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
> >>help
> >>  FBDEV helpers for KMS drivers.
> >>
> >>+config DRM_FBDEV_EMULATION
> >>+   bool "Enable legacy fbdev support for your modesetting driver"
> >>+   depends on DRM
> >>+   select DRM_KMS_HELPER
> >>+   select DRM_KMS_FB_HELPER
> >>+   select FB_SYS_FILLRECT
> >>+   select FB_SYS_COPYAREA
> >>+   select FB_SYS_IMAGEBLIT
> >>+   select FB_SYS_FOPS
> >>+   select FB_CFB_FILLRECT
> >>+   select FB_CFB_COPYAREA
> >>+   select FB_CFB_IMAGEBLIT
> >>+   default y
> >>+   help
> >>+ Choose this option if you have a need for the legacy fbdev
> >>+ support. Note that this support also provide the linux console
> >>+ support on top of your modesetting driver.
> >
> >Maybe clarify that for linux console support you also need
> >CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
> 
> DRM_KMS_FB_HELPER selects that for us, right?

Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
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Please read the FAQ at  http://www.tux.org/lkml/


Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Archit Taneja



On 03/10/2015 03:16 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

Legacy fbdev emulation support via DRM is achieved through KMS FB helpers.
Most modesetting drivers enable provide fbdev emulation by default by selecting
KMS FB helpers. A few provide a separate Kconfig option for the user to enable
or disbale fbdev emulation.

Enabling fbdev emulation is finally a distro-level decision. Having a top level
Kconfig option for fbdev emulation helps by providing a uniform way to
enable/disable fbdev emulation for any modesetting driver. It also lets us
remove unnecessary driver specific Kconfig options that causes bloat.

With a top level Kconfig in place, we can stub out the fb helper functions when
not needed without breaking functionality. Having stub functions also prevents
drivers to require wrapping fb helper function calls with #ifdefs.

DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by
default and majority of distributions expect the fbdev interface in the kernel.

For now, this config selects both FB_SYS_* and FB_CFB_* configs as some
modesetting drivers use the former and other the later. This needs to be taken
care of in a better way.

Signed-off-by: Archit Taneja 
---
  drivers/gpu/drm/Kconfig |  18 +++
  drivers/gpu/drm/Makefile|   4 ++
  include/drm/drm_fb_helper.h | 120 
  3 files changed, 142 insertions(+)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
  FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool "Enable legacy fbdev support for your modesetting driver"
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.
+
  config DRM_LOAD_EDID_FIRMWARE
bool "Allow to specify an EDID data set instead of probing for it"
depends on DRM_KMS_HELPER
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 2c239b9..c1d44b2 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -25,7 +25,11 @@ drm-$(CONFIG_OF) += drm_of.o
  drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o
  drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
+
+ifeq ($(CONFIG_DRM_FBDEV_EMULATION),y)
  drm_kms_helper-$(CONFIG_DRM_KMS_FB_HELPER) += drm_fb_helper.o
+endif


This should work as

drm_kms_helper-$CONFIG_DRM_FBDEV_EMULATION += drm_fb_helper.o

since both -y and -m are merged together.


Ah right. I'll fix that.

Archit

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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Archit Taneja



On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

Legacy fbdev emulation support via DRM is achieved through KMS FB helpers.
Most modesetting drivers enable provide fbdev emulation by default by selecting
KMS FB helpers. A few provide a separate Kconfig option for the user to enable
or disbale fbdev emulation.

Enabling fbdev emulation is finally a distro-level decision. Having a top level
Kconfig option for fbdev emulation helps by providing a uniform way to
enable/disable fbdev emulation for any modesetting driver. It also lets us
remove unnecessary driver specific Kconfig options that causes bloat.

With a top level Kconfig in place, we can stub out the fb helper functions when
not needed without breaking functionality. Having stub functions also prevents
drivers to require wrapping fb helper function calls with #ifdefs.

DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by
default and majority of distributions expect the fbdev interface in the kernel.

For now, this config selects both FB_SYS_* and FB_CFB_* configs as some
modesetting drivers use the former and other the later. This needs to be taken
care of in a better way.

Signed-off-by: Archit Taneja 
---
  drivers/gpu/drm/Kconfig |  18 +++
  drivers/gpu/drm/Makefile|   4 ++
  include/drm/drm_fb_helper.h | 120 
  3 files changed, 142 insertions(+)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
  FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool "Enable legacy fbdev support for your modesetting driver"
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.


Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.


DRM_KMS_FB_HELPER selects that for us, right?

Archit
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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Daniel Vetter
On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
> Legacy fbdev emulation support via DRM is achieved through KMS FB helpers.
> Most modesetting drivers enable provide fbdev emulation by default by 
> selecting
> KMS FB helpers. A few provide a separate Kconfig option for the user to enable
> or disbale fbdev emulation.
> 
> Enabling fbdev emulation is finally a distro-level decision. Having a top 
> level
> Kconfig option for fbdev emulation helps by providing a uniform way to
> enable/disable fbdev emulation for any modesetting driver. It also lets us
> remove unnecessary driver specific Kconfig options that causes bloat.
> 
> With a top level Kconfig in place, we can stub out the fb helper functions 
> when
> not needed without breaking functionality. Having stub functions also prevents
> drivers to require wrapping fb helper function calls with #ifdefs.
> 
> DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by
> default and majority of distributions expect the fbdev interface in the 
> kernel.
> 
> For now, this config selects both FB_SYS_* and FB_CFB_* configs as some
> modesetting drivers use the former and other the later. This needs to be taken
> care of in a better way.
> 
> Signed-off-by: Archit Taneja 
> ---
>  drivers/gpu/drm/Kconfig |  18 +++
>  drivers/gpu/drm/Makefile|   4 ++
>  include/drm/drm_fb_helper.h | 120 
> 
>  3 files changed, 142 insertions(+)
> 
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 151a050..38f83a0 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
>   help
> FBDEV helpers for KMS drivers.
>  
> +config DRM_FBDEV_EMULATION
> + bool "Enable legacy fbdev support for your modesetting driver"
> + depends on DRM
> + select DRM_KMS_HELPER
> + select DRM_KMS_FB_HELPER
> + select FB_SYS_FILLRECT
> + select FB_SYS_COPYAREA
> + select FB_SYS_IMAGEBLIT
> + select FB_SYS_FOPS
> + select FB_CFB_FILLRECT
> + select FB_CFB_COPYAREA
> + select FB_CFB_IMAGEBLIT
> + default y
> + help
> +   Choose this option if you have a need for the legacy fbdev
> +   support. Note that this support also provide the linux console
> +   support on top of your modesetting driver.

Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
-Daniel

> +
>  config DRM_LOAD_EDID_FIRMWARE
>   bool "Allow to specify an EDID data set instead of probing for it"
>   depends on DRM_KMS_HELPER
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 2c239b9..c1d44b2 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -25,7 +25,11 @@ drm-$(CONFIG_OF) += drm_of.o
>  drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
>   drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o
>  drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
> +
> +ifeq ($(CONFIG_DRM_FBDEV_EMULATION),y)
>  drm_kms_helper-$(CONFIG_DRM_KMS_FB_HELPER) += drm_fb_helper.o
> +endif
> +
>  drm_kms_helper-$(CONFIG_DRM_KMS_CMA_HELPER) += drm_fb_cma_helper.o
>  
>  obj-$(CONFIG_DRM_KMS_HELPER) += drm_kms_helper.o
> diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
> index 21b944c..dbfce1a 100644
> --- a/include/drm/drm_fb_helper.h
> +++ b/include/drm/drm_fb_helper.h
> @@ -103,6 +103,7 @@ struct drm_fb_helper {
>   bool delayed_hotplug;
>  };
>  
> +#ifdef CONFIG_DRM_FBDEV_EMULATION
>  void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper 
> *helper,
>  const struct drm_fb_helper_funcs *funcs);
>  int drm_fb_helper_init(struct drm_device *dev,
> @@ -139,4 +140,123 @@ drm_pick_cmdline_mode(struct drm_fb_helper_connector 
> *fb_helper_conn,
>  int drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper, struct 
> drm_connector *connector);
>  int drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper,
>  struct drm_connector *connector);
> +#else
> +static inline void drm_fb_helper_prepare(struct drm_device *dev,
> + struct drm_fb_helper *helper,
> + const struct drm_fb_helper_funcs *funcs)
> +{
> +}
> +
> +static inline int drm_fb_helper_init(struct drm_device *dev,
> +struct drm_fb_helper *helper, int crtc_count,
> +int max_conn)
> +{
> + return 0;
> +}
> +
> +static inline void drm_fb_helper_fini(struct drm_fb_helper *helper)
> +{
> +}
> +
> +static inline int drm_fb_helper_blank(int blank, struct fb_info *info)
> +{
> + return 0;
> +}
> +
> +static inline int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
> + struct fb_info *info)
> +{
> + 

Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Daniel Vetter
On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
> Legacy fbdev emulation support via DRM is achieved through KMS FB helpers.
> Most modesetting drivers enable provide fbdev emulation by default by 
> selecting
> KMS FB helpers. A few provide a separate Kconfig option for the user to enable
> or disbale fbdev emulation.
> 
> Enabling fbdev emulation is finally a distro-level decision. Having a top 
> level
> Kconfig option for fbdev emulation helps by providing a uniform way to
> enable/disable fbdev emulation for any modesetting driver. It also lets us
> remove unnecessary driver specific Kconfig options that causes bloat.
> 
> With a top level Kconfig in place, we can stub out the fb helper functions 
> when
> not needed without breaking functionality. Having stub functions also prevents
> drivers to require wrapping fb helper function calls with #ifdefs.
> 
> DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by
> default and majority of distributions expect the fbdev interface in the 
> kernel.
> 
> For now, this config selects both FB_SYS_* and FB_CFB_* configs as some
> modesetting drivers use the former and other the later. This needs to be taken
> care of in a better way.
> 
> Signed-off-by: Archit Taneja 
> ---
>  drivers/gpu/drm/Kconfig |  18 +++
>  drivers/gpu/drm/Makefile|   4 ++
>  include/drm/drm_fb_helper.h | 120 
> 
>  3 files changed, 142 insertions(+)
> 
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 151a050..38f83a0 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
>   help
> FBDEV helpers for KMS drivers.
>  
> +config DRM_FBDEV_EMULATION
> + bool "Enable legacy fbdev support for your modesetting driver"
> + depends on DRM
> + select DRM_KMS_HELPER
> + select DRM_KMS_FB_HELPER
> + select FB_SYS_FILLRECT
> + select FB_SYS_COPYAREA
> + select FB_SYS_IMAGEBLIT
> + select FB_SYS_FOPS
> + select FB_CFB_FILLRECT
> + select FB_CFB_COPYAREA
> + select FB_CFB_IMAGEBLIT
> + default y
> + help
> +   Choose this option if you have a need for the legacy fbdev
> +   support. Note that this support also provide the linux console
> +   support on top of your modesetting driver.
> +
>  config DRM_LOAD_EDID_FIRMWARE
>   bool "Allow to specify an EDID data set instead of probing for it"
>   depends on DRM_KMS_HELPER
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 2c239b9..c1d44b2 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -25,7 +25,11 @@ drm-$(CONFIG_OF) += drm_of.o
>  drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
>   drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o
>  drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
> +
> +ifeq ($(CONFIG_DRM_FBDEV_EMULATION),y)
>  drm_kms_helper-$(CONFIG_DRM_KMS_FB_HELPER) += drm_fb_helper.o
> +endif

This should work as

drm_kms_helper-$CONFIG_DRM_FBDEV_EMULATION += drm_fb_helper.o

since both -y and -m are merged together.
-Daniel

> +
>  drm_kms_helper-$(CONFIG_DRM_KMS_CMA_HELPER) += drm_fb_cma_helper.o
>  
>  obj-$(CONFIG_DRM_KMS_HELPER) += drm_kms_helper.o
> diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
> index 21b944c..dbfce1a 100644
> --- a/include/drm/drm_fb_helper.h
> +++ b/include/drm/drm_fb_helper.h
> @@ -103,6 +103,7 @@ struct drm_fb_helper {
>   bool delayed_hotplug;
>  };
>  
> +#ifdef CONFIG_DRM_FBDEV_EMULATION
>  void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper 
> *helper,
>  const struct drm_fb_helper_funcs *funcs);
>  int drm_fb_helper_init(struct drm_device *dev,
> @@ -139,4 +140,123 @@ drm_pick_cmdline_mode(struct drm_fb_helper_connector 
> *fb_helper_conn,
>  int drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper, struct 
> drm_connector *connector);
>  int drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper,
>  struct drm_connector *connector);
> +#else
> +static inline void drm_fb_helper_prepare(struct drm_device *dev,
> + struct drm_fb_helper *helper,
> + const struct drm_fb_helper_funcs *funcs)
> +{
> +}
> +
> +static inline int drm_fb_helper_init(struct drm_device *dev,
> +struct drm_fb_helper *helper, int crtc_count,
> +int max_conn)
> +{
> + return 0;
> +}
> +
> +static inline void drm_fb_helper_fini(struct drm_fb_helper *helper)
> +{
> +}
> +
> +static inline int drm_fb_helper_blank(int blank, struct fb_info *info)
> +{
> + return 0;
> +}
> +
> +static inline int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
> + struct fb_info *info)
> +{

Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Archit Taneja



On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

Legacy fbdev emulation support via DRM is achieved through KMS FB helpers.
Most modesetting drivers enable provide fbdev emulation by default by selecting
KMS FB helpers. A few provide a separate Kconfig option for the user to enable
or disbale fbdev emulation.

Enabling fbdev emulation is finally a distro-level decision. Having a top level
Kconfig option for fbdev emulation helps by providing a uniform way to
enable/disable fbdev emulation for any modesetting driver. It also lets us
remove unnecessary driver specific Kconfig options that causes bloat.

With a top level Kconfig in place, we can stub out the fb helper functions when
not needed without breaking functionality. Having stub functions also prevents
drivers to require wrapping fb helper function calls with #ifdefs.

DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by
default and majority of distributions expect the fbdev interface in the kernel.

For now, this config selects both FB_SYS_* and FB_CFB_* configs as some
modesetting drivers use the former and other the later. This needs to be taken
care of in a better way.

Signed-off-by: Archit Taneja arch...@codeaurora.org
---
  drivers/gpu/drm/Kconfig |  18 +++
  drivers/gpu/drm/Makefile|   4 ++
  include/drm/drm_fb_helper.h | 120 
  3 files changed, 142 insertions(+)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
  FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool Enable legacy fbdev support for your modesetting driver
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.


Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.


DRM_KMS_FB_HELPER selects that for us, right?

Archit
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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Daniel Vetter
On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
 Legacy fbdev emulation support via DRM is achieved through KMS FB helpers.
 Most modesetting drivers enable provide fbdev emulation by default by 
 selecting
 KMS FB helpers. A few provide a separate Kconfig option for the user to enable
 or disbale fbdev emulation.
 
 Enabling fbdev emulation is finally a distro-level decision. Having a top 
 level
 Kconfig option for fbdev emulation helps by providing a uniform way to
 enable/disable fbdev emulation for any modesetting driver. It also lets us
 remove unnecessary driver specific Kconfig options that causes bloat.
 
 With a top level Kconfig in place, we can stub out the fb helper functions 
 when
 not needed without breaking functionality. Having stub functions also prevents
 drivers to require wrapping fb helper function calls with #ifdefs.
 
 DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by
 default and majority of distributions expect the fbdev interface in the 
 kernel.
 
 For now, this config selects both FB_SYS_* and FB_CFB_* configs as some
 modesetting drivers use the former and other the later. This needs to be taken
 care of in a better way.
 
 Signed-off-by: Archit Taneja arch...@codeaurora.org
 ---
  drivers/gpu/drm/Kconfig |  18 +++
  drivers/gpu/drm/Makefile|   4 ++
  include/drm/drm_fb_helper.h | 120 
 
  3 files changed, 142 insertions(+)
 
 diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
 index 151a050..38f83a0 100644
 --- a/drivers/gpu/drm/Kconfig
 +++ b/drivers/gpu/drm/Kconfig
 @@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
   help
 FBDEV helpers for KMS drivers.
  
 +config DRM_FBDEV_EMULATION
 + bool Enable legacy fbdev support for your modesetting driver
 + depends on DRM
 + select DRM_KMS_HELPER
 + select DRM_KMS_FB_HELPER
 + select FB_SYS_FILLRECT
 + select FB_SYS_COPYAREA
 + select FB_SYS_IMAGEBLIT
 + select FB_SYS_FOPS
 + select FB_CFB_FILLRECT
 + select FB_CFB_COPYAREA
 + select FB_CFB_IMAGEBLIT
 + default y
 + help
 +   Choose this option if you have a need for the legacy fbdev
 +   support. Note that this support also provide the linux console
 +   support on top of your modesetting driver.
 +
  config DRM_LOAD_EDID_FIRMWARE
   bool Allow to specify an EDID data set instead of probing for it
   depends on DRM_KMS_HELPER
 diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
 index 2c239b9..c1d44b2 100644
 --- a/drivers/gpu/drm/Makefile
 +++ b/drivers/gpu/drm/Makefile
 @@ -25,7 +25,11 @@ drm-$(CONFIG_OF) += drm_of.o
  drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
   drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o
  drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
 +
 +ifeq ($(CONFIG_DRM_FBDEV_EMULATION),y)
  drm_kms_helper-$(CONFIG_DRM_KMS_FB_HELPER) += drm_fb_helper.o
 +endif

This should work as

drm_kms_helper-$CONFIG_DRM_FBDEV_EMULATION += drm_fb_helper.o

since both modename-y and modename-m are merged together.
-Daniel

 +
  drm_kms_helper-$(CONFIG_DRM_KMS_CMA_HELPER) += drm_fb_cma_helper.o
  
  obj-$(CONFIG_DRM_KMS_HELPER) += drm_kms_helper.o
 diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
 index 21b944c..dbfce1a 100644
 --- a/include/drm/drm_fb_helper.h
 +++ b/include/drm/drm_fb_helper.h
 @@ -103,6 +103,7 @@ struct drm_fb_helper {
   bool delayed_hotplug;
  };
  
 +#ifdef CONFIG_DRM_FBDEV_EMULATION
  void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper 
 *helper,
  const struct drm_fb_helper_funcs *funcs);
  int drm_fb_helper_init(struct drm_device *dev,
 @@ -139,4 +140,123 @@ drm_pick_cmdline_mode(struct drm_fb_helper_connector 
 *fb_helper_conn,
  int drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper, struct 
 drm_connector *connector);
  int drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper,
  struct drm_connector *connector);
 +#else
 +static inline void drm_fb_helper_prepare(struct drm_device *dev,
 + struct drm_fb_helper *helper,
 + const struct drm_fb_helper_funcs *funcs)
 +{
 +}
 +
 +static inline int drm_fb_helper_init(struct drm_device *dev,
 +struct drm_fb_helper *helper, int crtc_count,
 +int max_conn)
 +{
 + return 0;
 +}
 +
 +static inline void drm_fb_helper_fini(struct drm_fb_helper *helper)
 +{
 +}
 +
 +static inline int drm_fb_helper_blank(int blank, struct fb_info *info)
 +{
 + return 0;
 +}
 +
 +static inline int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
 + struct fb_info *info)
 +{
 + return 0;
 +}
 +
 +static inline int drm_fb_helper_set_par(struct fb_info *info)
 

Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Daniel Vetter
On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
 
 
 On 03/10/2015 03:17 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
 Legacy fbdev emulation support via DRM is achieved through KMS FB helpers.
 Most modesetting drivers enable provide fbdev emulation by default by 
 selecting
 KMS FB helpers. A few provide a separate Kconfig option for the user to 
 enable
 or disbale fbdev emulation.
 
 Enabling fbdev emulation is finally a distro-level decision. Having a top 
 level
 Kconfig option for fbdev emulation helps by providing a uniform way to
 enable/disable fbdev emulation for any modesetting driver. It also lets us
 remove unnecessary driver specific Kconfig options that causes bloat.
 
 With a top level Kconfig in place, we can stub out the fb helper functions 
 when
 not needed without breaking functionality. Having stub functions also 
 prevents
 drivers to require wrapping fb helper function calls with #ifdefs.
 
 DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation 
 by
 default and majority of distributions expect the fbdev interface in the 
 kernel.
 
 For now, this config selects both FB_SYS_* and FB_CFB_* configs as some
 modesetting drivers use the former and other the later. This needs to be 
 taken
 care of in a better way.
 
 Signed-off-by: Archit Taneja arch...@codeaurora.org
 ---
   drivers/gpu/drm/Kconfig |  18 +++
   drivers/gpu/drm/Makefile|   4 ++
   include/drm/drm_fb_helper.h | 120 
  
   3 files changed, 142 insertions(+)
 
 diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
 index 151a050..38f83a0 100644
 --- a/drivers/gpu/drm/Kconfig
 +++ b/drivers/gpu/drm/Kconfig
 @@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
 help
   FBDEV helpers for KMS drivers.
 
 +config DRM_FBDEV_EMULATION
 +   bool Enable legacy fbdev support for your modesetting driver
 +   depends on DRM
 +   select DRM_KMS_HELPER
 +   select DRM_KMS_FB_HELPER
 +   select FB_SYS_FILLRECT
 +   select FB_SYS_COPYAREA
 +   select FB_SYS_IMAGEBLIT
 +   select FB_SYS_FOPS
 +   select FB_CFB_FILLRECT
 +   select FB_CFB_COPYAREA
 +   select FB_CFB_IMAGEBLIT
 +   default y
 +   help
 + Choose this option if you have a need for the legacy fbdev
 + support. Note that this support also provide the linux console
 + support on top of your modesetting driver.
 
 Maybe clarify that for linux console support you also need
 CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
 
 DRM_KMS_FB_HELPER selects that for us, right?

Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Daniel Vetter
On Tue, Mar 10, 2015 at 03:52:41PM +0530, Archit Taneja wrote:
 On 03/10/2015 03:35 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:
 On 03/10/2015 03:17 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
 diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
 index 151a050..38f83a0 100644
 --- a/drivers/gpu/drm/Kconfig
 +++ b/drivers/gpu/drm/Kconfig
 @@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
   help
 FBDEV helpers for KMS drivers.
 
 +config DRM_FBDEV_EMULATION
 + bool Enable legacy fbdev support for your modesetting driver
 + depends on DRM
 + select DRM_KMS_HELPER
 + select DRM_KMS_FB_HELPER
 + select FB_SYS_FILLRECT
 + select FB_SYS_COPYAREA
 + select FB_SYS_IMAGEBLIT
 + select FB_SYS_FOPS
 + select FB_CFB_FILLRECT
 + select FB_CFB_COPYAREA
 + select FB_CFB_IMAGEBLIT
 + default y
 + help
 +   Choose this option if you have a need for the legacy fbdev
 +   support. Note that this support also provide the linux console
 +   support on top of your modesetting driver.
 
 Maybe clarify that for linux console support you also need
 CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
 
 DRM_KMS_FB_HELPER selects that for us, right?
 
 Hm right I've missed that. Reminds me that you need one more patch at the
 end to remove all the various select DRM_KMS_FB_HELPER from all drm
 drivers. Otherwise this knob here won't work by default if you e.g. select
 radeon. In general we can't mix explicit options with menu entries with a
 select.
 
 I was trying that out. Removing DRM_KMS_FB_HELPER and having
 DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff internally in
 their respective xyz_fbdev.c files.

But with the stubbed out functions that should work, right? Why doesn't
it?

 Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers and
 replace them with 'select DRM_FBDEV_EMULATION'?
 
 Another option would be to provide #ifdef DRM_FBDEV_EMULATION wrap-arounds
 for fb related function calls/declarations in each driver, something that's
 already done for i915 and msm drivers.

The problem with the patch as-is the massive amounts of selects the FB
helper still has. We need to get rid of them so that when you disable
fbdev emulation you can indeed disable fbcon and the entire fbdev
subsystem. I've thought that remove the hidden symbol DRM_KMS_FB_HELPER
and moving all the selects to DRM_FBDEV_EMULATION should work out? If that
doesn't work we need to look again how to better stub things out I think.
-Daniel
-- 
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Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Daniel Vetter
On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
 Legacy fbdev emulation support via DRM is achieved through KMS FB helpers.
 Most modesetting drivers enable provide fbdev emulation by default by 
 selecting
 KMS FB helpers. A few provide a separate Kconfig option for the user to enable
 or disbale fbdev emulation.
 
 Enabling fbdev emulation is finally a distro-level decision. Having a top 
 level
 Kconfig option for fbdev emulation helps by providing a uniform way to
 enable/disable fbdev emulation for any modesetting driver. It also lets us
 remove unnecessary driver specific Kconfig options that causes bloat.
 
 With a top level Kconfig in place, we can stub out the fb helper functions 
 when
 not needed without breaking functionality. Having stub functions also prevents
 drivers to require wrapping fb helper function calls with #ifdefs.
 
 DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by
 default and majority of distributions expect the fbdev interface in the 
 kernel.
 
 For now, this config selects both FB_SYS_* and FB_CFB_* configs as some
 modesetting drivers use the former and other the later. This needs to be taken
 care of in a better way.
 
 Signed-off-by: Archit Taneja arch...@codeaurora.org
 ---
  drivers/gpu/drm/Kconfig |  18 +++
  drivers/gpu/drm/Makefile|   4 ++
  include/drm/drm_fb_helper.h | 120 
 
  3 files changed, 142 insertions(+)
 
 diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
 index 151a050..38f83a0 100644
 --- a/drivers/gpu/drm/Kconfig
 +++ b/drivers/gpu/drm/Kconfig
 @@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
   help
 FBDEV helpers for KMS drivers.
  
 +config DRM_FBDEV_EMULATION
 + bool Enable legacy fbdev support for your modesetting driver
 + depends on DRM
 + select DRM_KMS_HELPER
 + select DRM_KMS_FB_HELPER
 + select FB_SYS_FILLRECT
 + select FB_SYS_COPYAREA
 + select FB_SYS_IMAGEBLIT
 + select FB_SYS_FOPS
 + select FB_CFB_FILLRECT
 + select FB_CFB_COPYAREA
 + select FB_CFB_IMAGEBLIT
 + default y
 + help
 +   Choose this option if you have a need for the legacy fbdev
 +   support. Note that this support also provide the linux console
 +   support on top of your modesetting driver.

Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.
-Daniel

 +
  config DRM_LOAD_EDID_FIRMWARE
   bool Allow to specify an EDID data set instead of probing for it
   depends on DRM_KMS_HELPER
 diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
 index 2c239b9..c1d44b2 100644
 --- a/drivers/gpu/drm/Makefile
 +++ b/drivers/gpu/drm/Makefile
 @@ -25,7 +25,11 @@ drm-$(CONFIG_OF) += drm_of.o
  drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
   drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o
  drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
 +
 +ifeq ($(CONFIG_DRM_FBDEV_EMULATION),y)
  drm_kms_helper-$(CONFIG_DRM_KMS_FB_HELPER) += drm_fb_helper.o
 +endif
 +
  drm_kms_helper-$(CONFIG_DRM_KMS_CMA_HELPER) += drm_fb_cma_helper.o
  
  obj-$(CONFIG_DRM_KMS_HELPER) += drm_kms_helper.o
 diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h
 index 21b944c..dbfce1a 100644
 --- a/include/drm/drm_fb_helper.h
 +++ b/include/drm/drm_fb_helper.h
 @@ -103,6 +103,7 @@ struct drm_fb_helper {
   bool delayed_hotplug;
  };
  
 +#ifdef CONFIG_DRM_FBDEV_EMULATION
  void drm_fb_helper_prepare(struct drm_device *dev, struct drm_fb_helper 
 *helper,
  const struct drm_fb_helper_funcs *funcs);
  int drm_fb_helper_init(struct drm_device *dev,
 @@ -139,4 +140,123 @@ drm_pick_cmdline_mode(struct drm_fb_helper_connector 
 *fb_helper_conn,
  int drm_fb_helper_add_one_connector(struct drm_fb_helper *fb_helper, struct 
 drm_connector *connector);
  int drm_fb_helper_remove_one_connector(struct drm_fb_helper *fb_helper,
  struct drm_connector *connector);
 +#else
 +static inline void drm_fb_helper_prepare(struct drm_device *dev,
 + struct drm_fb_helper *helper,
 + const struct drm_fb_helper_funcs *funcs)
 +{
 +}
 +
 +static inline int drm_fb_helper_init(struct drm_device *dev,
 +struct drm_fb_helper *helper, int crtc_count,
 +int max_conn)
 +{
 + return 0;
 +}
 +
 +static inline void drm_fb_helper_fini(struct drm_fb_helper *helper)
 +{
 +}
 +
 +static inline int drm_fb_helper_blank(int blank, struct fb_info *info)
 +{
 + return 0;
 +}
 +
 +static inline int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
 + struct fb_info *info)
 +{
 + return 0;
 +}
 +
 +static inline int drm_fb_helper_set_par(struct fb_info *info)
 +{
 + return 0;
 +}
 +
 

Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Archit Taneja



On 03/10/2015 03:35 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:



On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

Legacy fbdev emulation support via DRM is achieved through KMS FB helpers.
Most modesetting drivers enable provide fbdev emulation by default by selecting
KMS FB helpers. A few provide a separate Kconfig option for the user to enable
or disbale fbdev emulation.

Enabling fbdev emulation is finally a distro-level decision. Having a top level
Kconfig option for fbdev emulation helps by providing a uniform way to
enable/disable fbdev emulation for any modesetting driver. It also lets us
remove unnecessary driver specific Kconfig options that causes bloat.

With a top level Kconfig in place, we can stub out the fb helper functions when
not needed without breaking functionality. Having stub functions also prevents
drivers to require wrapping fb helper function calls with #ifdefs.

DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by
default and majority of distributions expect the fbdev interface in the kernel.

For now, this config selects both FB_SYS_* and FB_CFB_* configs as some
modesetting drivers use the former and other the later. This needs to be taken
care of in a better way.

Signed-off-by: Archit Taneja arch...@codeaurora.org
---
  drivers/gpu/drm/Kconfig |  18 +++
  drivers/gpu/drm/Makefile|   4 ++
  include/drm/drm_fb_helper.h | 120 
  3 files changed, 142 insertions(+)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
  FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool Enable legacy fbdev support for your modesetting driver
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.


Maybe clarify that for linux console support you also need
CONFIG_FRAMEBUFFER_CONSOLE? fbdev alone isn't enough.


DRM_KMS_FB_HELPER selects that for us, right?


Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.


I was trying that out. Removing DRM_KMS_FB_HELPER and having 
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff 
internally in their respective xyz_fbdev.c files.


Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers 
and replace them with 'select DRM_FBDEV_EMULATION'?


Another option would be to provide #ifdef DRM_FBDEV_EMULATION 
wrap-arounds for fb related function calls/declarations in each driver, 
something that's already done for i915 and msm drivers.


Archit

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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Archit Taneja



On 03/10/2015 03:16 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

Legacy fbdev emulation support via DRM is achieved through KMS FB helpers.
Most modesetting drivers enable provide fbdev emulation by default by selecting
KMS FB helpers. A few provide a separate Kconfig option for the user to enable
or disbale fbdev emulation.

Enabling fbdev emulation is finally a distro-level decision. Having a top level
Kconfig option for fbdev emulation helps by providing a uniform way to
enable/disable fbdev emulation for any modesetting driver. It also lets us
remove unnecessary driver specific Kconfig options that causes bloat.

With a top level Kconfig in place, we can stub out the fb helper functions when
not needed without breaking functionality. Having stub functions also prevents
drivers to require wrapping fb helper function calls with #ifdefs.

DRM_FBDEV_EMULATION defaults to y since many drivers enable fbdev emulation by
default and majority of distributions expect the fbdev interface in the kernel.

For now, this config selects both FB_SYS_* and FB_CFB_* configs as some
modesetting drivers use the former and other the later. This needs to be taken
care of in a better way.

Signed-off-by: Archit Taneja arch...@codeaurora.org
---
  drivers/gpu/drm/Kconfig |  18 +++
  drivers/gpu/drm/Makefile|   4 ++
  include/drm/drm_fb_helper.h | 120 
  3 files changed, 142 insertions(+)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 151a050..38f83a0 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -40,6 +40,24 @@ config DRM_KMS_FB_HELPER
help
  FBDEV helpers for KMS drivers.

+config DRM_FBDEV_EMULATION
+   bool Enable legacy fbdev support for your modesetting driver
+   depends on DRM
+   select DRM_KMS_HELPER
+   select DRM_KMS_FB_HELPER
+   select FB_SYS_FILLRECT
+   select FB_SYS_COPYAREA
+   select FB_SYS_IMAGEBLIT
+   select FB_SYS_FOPS
+   select FB_CFB_FILLRECT
+   select FB_CFB_COPYAREA
+   select FB_CFB_IMAGEBLIT
+   default y
+   help
+ Choose this option if you have a need for the legacy fbdev
+ support. Note that this support also provide the linux console
+ support on top of your modesetting driver.
+
  config DRM_LOAD_EDID_FIRMWARE
bool Allow to specify an EDID data set instead of probing for it
depends on DRM_KMS_HELPER
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 2c239b9..c1d44b2 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -25,7 +25,11 @@ drm-$(CONFIG_OF) += drm_of.o
  drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o
  drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
+
+ifeq ($(CONFIG_DRM_FBDEV_EMULATION),y)
  drm_kms_helper-$(CONFIG_DRM_KMS_FB_HELPER) += drm_fb_helper.o
+endif


This should work as

drm_kms_helper-$CONFIG_DRM_FBDEV_EMULATION += drm_fb_helper.o

since both modename-y and modename-m are merged together.


Ah right. I'll fix that.

Archit

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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Archit Taneja



On 03/10/2015 09:03 PM, Jani Nikula wrote:

On Tue, 10 Mar 2015, Archit Taneja arch...@codeaurora.org wrote:

On 03/10/2015 03:35 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:



On 03/10/2015 03:17 PM, Daniel Vetter wrote:

On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:

DRM_KMS_FB_HELPER selects that for us, right?


Hm right I've missed that. Reminds me that you need one more patch at the
end to remove all the various select DRM_KMS_FB_HELPER from all drm
drivers. Otherwise this knob here won't work by default if you e.g. select
radeon. In general we can't mix explicit options with menu entries with a
select.


I was trying that out. Removing DRM_KMS_FB_HELPER and having
DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff
internally in their respective xyz_fbdev.c files.

Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers
and replace them with 'select DRM_FBDEV_EMULATION'?


Slightly tangential: As a rule of thumb, you should not select
anything that is visible in menuconfig or has dependencies [1]. This
will break the build eventually, and attempts to fix it are troublesome
[2].


Thanks, I'll keep this in mind!

Archit

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Re: [RFC 1/6] drm: Add top level Kconfig option for DRM fbdev emulation

2015-03-10 Thread Jani Nikula
On Tue, 10 Mar 2015, Archit Taneja arch...@codeaurora.org wrote:
 On 03/10/2015 03:35 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:22:49PM +0530, Archit Taneja wrote:


 On 03/10/2015 03:17 PM, Daniel Vetter wrote:
 On Tue, Mar 10, 2015 at 03:11:28PM +0530, Archit Taneja wrote:
 DRM_KMS_FB_HELPER selects that for us, right?

 Hm right I've missed that. Reminds me that you need one more patch at the
 end to remove all the various select DRM_KMS_FB_HELPER from all drm
 drivers. Otherwise this knob here won't work by default if you e.g. select
 radeon. In general we can't mix explicit options with menu entries with a
 select.

 I was trying that out. Removing DRM_KMS_FB_HELPER and having 
 DRM_FBDEV_EMULATION disabled breaks drivers which use FB stuff 
 internally in their respective xyz_fbdev.c files.

 Are you saying that we should remove DRM_KMS_FB_HELPER for such drivers 
 and replace them with 'select DRM_FBDEV_EMULATION'?

Slightly tangential: As a rule of thumb, you should not select
anything that is visible in menuconfig or has dependencies [1]. This
will break the build eventually, and attempts to fix it are troublesome
[2].

BR,
Jani.

[1] Documentation/kbuild/kconfig-language.txt
[2] http://mid.gmane.org/1413580403-16225-1-git-send-email-jani.nik...@intel.com


-- 
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