Re: [PATCH 1/2] drm/dp_aux: Use non-cyclic idr, add suffix option for aux device
On Wed, 2019-04-17 at 23:10 +, Li, Sun peng (Leo) wrote:
>
>
> On 2019-04-16 6:16 p.m., Lyude Paul wrote:
> > Sorry for the slow response, I've been really busy ;_;
>
> No worries :)
>
> > On Fri, 2019-04-12 at 12:05 -0400, sunpeng...@amd.com wrote:
> > > From: Leo Li
> > >
> > > In preparation for adding aux devices for DP MST:
> > >
> > > 1. A non-cyclic idr is used for the device minor version. That way,
> > > hotplug cycling MST devices won't needlessly increment the minor
> > > version index.
> >
> > I really like this btw, cyclic idrs are really annoying for drm_dp_aux_dev,
> > even outside of MST (try reloading a drm driver a couple of times and you'll
> > understand ;). I think we should split this into another commit though
> >
> > > 2. A suffix option is added to the aux device file name. It can be used
> > > to identify the corresponding MST device.
> >
> > I like this idea, but I think there may be a better way that we can do this.
> > Using /dev/nvme* as an example, we have the standard dev paths (/dev/nvme0,
> > /dev/nvme0n1, etc.). But we can also access them through /dev/disk/by-
> > {id,label,partlabel,partuuid,path,uuid}.
> >
> > So what if we added something similar for aux devices? We start off with the
> > standard /dev/drm_dp_aux*, then provide more descriptive symlinks and
> > directories:
> >
> > (feel free to come up with better naming then this if you can)
> >
> > /dev/drm_dp_aux/card0-DP-1 -> /dev/drm_dp_aux1
> > /dev/drm_dp_aux/card0-DP-2 -> /dev/drm_dp_aux2
> > etc.
>
> That does sound neater - although FWICT, this will have to be done with
> udev rules?
>
> I took a brief look at how that's done for storage devices. It looks
> like they have rules defined in
> /lib/udev/rules.d/60-persistent-storage.rules that manages the "by-x"
> symlinks.
>
> To make this happen for aux devices, what we could do is attach sysfs
> attributes to the device. It can then be parsed by udev in a similar
> fashion. Currently, only 'name' attribute is attached, as seen in
> drm_dp_aux_dev.c (after name_show()).
Yeah-that sounds perfect to me!
>
> Thanks,
> Leo
>
> > > Signed-off-by: Leo Li
> > > ---
> > > drivers/gpu/drm/drm_crtc_helper_internal.h | 5 +++--
> > > drivers/gpu/drm/drm_dp_aux_dev.c | 8
> > > drivers/gpu/drm/drm_dp_helper.c| 2 +-
> > > 3 files changed, 8 insertions(+), 7 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/drm_crtc_helper_internal.h
> > > b/drivers/gpu/drm/drm_crtc_helper_internal.h
> > > index b5ac158..9f0907b 100644
> > > --- a/drivers/gpu/drm/drm_crtc_helper_internal.h
> > > +++ b/drivers/gpu/drm/drm_crtc_helper_internal.h
> > > @@ -46,7 +46,7 @@ static inline int drm_fb_helper_modinit(void)
> > > #ifdef CONFIG_DRM_DP_AUX_CHARDEV
> > > int drm_dp_aux_dev_init(void);
> > > void drm_dp_aux_dev_exit(void);
> > > -int drm_dp_aux_register_devnode(struct drm_dp_aux *aux);
> > > +int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char
> > > *suffix);
> > > void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux);
> > > #else
> > > static inline int drm_dp_aux_dev_init(void)
> > > @@ -58,7 +58,8 @@ static inline void drm_dp_aux_dev_exit(void)
> > > {
> > > }
> > >
> > > -static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
> > > +static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux,
> > > + const char *suffix)
> > > {
> > > return 0;
> > > }
> > > diff --git a/drivers/gpu/drm/drm_dp_aux_dev.c
> > > b/drivers/gpu/drm/drm_dp_aux_dev.c
> > > index 0e4f25d..2310a67 100644
> > > --- a/drivers/gpu/drm/drm_dp_aux_dev.c
> > > +++ b/drivers/gpu/drm/drm_dp_aux_dev.c
> > > @@ -80,8 +80,7 @@ static struct drm_dp_aux_dev
> > > *alloc_drm_dp_aux_dev(struct
> > > drm_dp_aux *aux)
> > > kref_init(_dev->refcount);
> > >
> > > mutex_lock(_idr_mutex);
> > > - index = idr_alloc_cyclic(_idr, aux_dev, 0, DRM_AUX_MINORS,
> > > - GFP_KERNEL);
> > > + index = idr_alloc(_idr, aux_dev, 0, DRM_AUX_MINORS, GFP_KERNEL);
> > > mutex_unlock(_idr_mutex);
> > > if (index < 0) {
> > > kfree(aux_dev);
> > > @@ -290,7 +289,7 @@ void drm_dp_aux_unregister_devnode(struct drm_dp_aux
> > > *aux)
> > > kref_put(_dev->refcount, release_drm_dp_aux_dev);
> > > }
> > >
> > > -int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
> > > +int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char
> > > *suffix)
> > > {
> > > struct drm_dp_aux_dev *aux_dev;
> > > int res;
> > > @@ -301,7 +300,8 @@ int drm_dp_aux_register_devnode(struct drm_dp_aux
> > > *aux)
> > >
> > > aux_dev->dev = device_create(drm_dp_aux_dev_class, aux->dev,
> > >MKDEV(drm_dev_major, aux_dev-
> > > >index),
> > > NULL,
> > > - "drm_dp_aux%d",
Re: [PATCH 1/2] drm/dp_aux: Use non-cyclic idr, add suffix option for aux device
On 2019-04-16 6:16 p.m., Lyude Paul wrote:
> Sorry for the slow response, I've been really busy ;_;
No worries :)
>
> On Fri, 2019-04-12 at 12:05 -0400, sunpeng...@amd.com wrote:
>> From: Leo Li
>>
>> In preparation for adding aux devices for DP MST:
>>
>> 1. A non-cyclic idr is used for the device minor version. That way,
>> hotplug cycling MST devices won't needlessly increment the minor
>> version index.
>
> I really like this btw, cyclic idrs are really annoying for drm_dp_aux_dev,
> even outside of MST (try reloading a drm driver a couple of times and you'll
> understand ;). I think we should split this into another commit though
>
>> 2. A suffix option is added to the aux device file name. It can be used
>> to identify the corresponding MST device.
>
> I like this idea, but I think there may be a better way that we can do this.
> Using /dev/nvme* as an example, we have the standard dev paths (/dev/nvme0,
> /dev/nvme0n1, etc.). But we can also access them through /dev/disk/by-
> {id,label,partlabel,partuuid,path,uuid}.
>
> So what if we added something similar for aux devices? We start off with the
> standard /dev/drm_dp_aux*, then provide more descriptive symlinks and
> directories:
>
> (feel free to come up with better naming then this if you can)
>
> /dev/drm_dp_aux/card0-DP-1 -> /dev/drm_dp_aux1
> /dev/drm_dp_aux/card0-DP-2 -> /dev/drm_dp_aux2
> etc.
That does sound neater - although FWICT, this will have to be done with
udev rules?
I took a brief look at how that's done for storage devices. It looks
like they have rules defined in
/lib/udev/rules.d/60-persistent-storage.rules that manages the "by-x"
symlinks.
To make this happen for aux devices, what we could do is attach sysfs
attributes to the device. It can then be parsed by udev in a similar
fashion. Currently, only 'name' attribute is attached, as seen in
drm_dp_aux_dev.c (after name_show()).
Thanks,
Leo
>
>>
>> Signed-off-by: Leo Li
>> ---
>> drivers/gpu/drm/drm_crtc_helper_internal.h | 5 +++--
>> drivers/gpu/drm/drm_dp_aux_dev.c | 8
>> drivers/gpu/drm/drm_dp_helper.c| 2 +-
>> 3 files changed, 8 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_crtc_helper_internal.h
>> b/drivers/gpu/drm/drm_crtc_helper_internal.h
>> index b5ac158..9f0907b 100644
>> --- a/drivers/gpu/drm/drm_crtc_helper_internal.h
>> +++ b/drivers/gpu/drm/drm_crtc_helper_internal.h
>> @@ -46,7 +46,7 @@ static inline int drm_fb_helper_modinit(void)
>> #ifdef CONFIG_DRM_DP_AUX_CHARDEV
>> int drm_dp_aux_dev_init(void);
>> void drm_dp_aux_dev_exit(void);
>> -int drm_dp_aux_register_devnode(struct drm_dp_aux *aux);
>> +int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char
>> *suffix);
>> void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux);
>> #else
>> static inline int drm_dp_aux_dev_init(void)
>> @@ -58,7 +58,8 @@ static inline void drm_dp_aux_dev_exit(void)
>> {
>> }
>>
>> -static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
>> +static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux,
>> + const char *suffix)
>> {
>> return 0;
>> }
>> diff --git a/drivers/gpu/drm/drm_dp_aux_dev.c
>> b/drivers/gpu/drm/drm_dp_aux_dev.c
>> index 0e4f25d..2310a67 100644
>> --- a/drivers/gpu/drm/drm_dp_aux_dev.c
>> +++ b/drivers/gpu/drm/drm_dp_aux_dev.c
>> @@ -80,8 +80,7 @@ static struct drm_dp_aux_dev *alloc_drm_dp_aux_dev(struct
>> drm_dp_aux *aux)
>> kref_init(_dev->refcount);
>>
>> mutex_lock(_idr_mutex);
>> -index = idr_alloc_cyclic(_idr, aux_dev, 0, DRM_AUX_MINORS,
>> - GFP_KERNEL);
>> +index = idr_alloc(_idr, aux_dev, 0, DRM_AUX_MINORS, GFP_KERNEL);
>> mutex_unlock(_idr_mutex);
>> if (index < 0) {
>> kfree(aux_dev);
>> @@ -290,7 +289,7 @@ void drm_dp_aux_unregister_devnode(struct drm_dp_aux
>> *aux)
>> kref_put(_dev->refcount, release_drm_dp_aux_dev);
>> }
>>
>> -int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
>> +int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char *suffix)
>> {
>> struct drm_dp_aux_dev *aux_dev;
>> int res;
>> @@ -301,7 +300,8 @@ int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
>>
>> aux_dev->dev = device_create(drm_dp_aux_dev_class, aux->dev,
>> MKDEV(drm_dev_major, aux_dev->index),
>> NULL,
>> - "drm_dp_aux%d", aux_dev->index);
>> + "drm_dp_aux%d%s", aux_dev->index,
>> + suffix ? suffix : "");
>> if (IS_ERR(aux_dev->dev)) {
>> res = PTR_ERR(aux_dev->dev);
>> aux_dev->dev = NULL;
>> diff --git a/drivers/gpu/drm/drm_dp_helper.c
>> b/drivers/gpu/drm/drm_dp_helper.c
>> index e2266ac..13f1005 100644
>> --- a/drivers/gpu/drm/drm_dp_helper.c
>> +++ b/drivers/gpu/drm/drm_dp_helper.c
>>
Re: [PATCH 1/2] drm/dp_aux: Use non-cyclic idr, add suffix option for aux device
Sorry for the slow response, I've been really busy ;_;
On Fri, 2019-04-12 at 12:05 -0400, sunpeng...@amd.com wrote:
> From: Leo Li
>
> In preparation for adding aux devices for DP MST:
>
> 1. A non-cyclic idr is used for the device minor version. That way,
>hotplug cycling MST devices won't needlessly increment the minor
>version index.
I really like this btw, cyclic idrs are really annoying for drm_dp_aux_dev,
even outside of MST (try reloading a drm driver a couple of times and you'll
understand ;). I think we should split this into another commit though
> 2. A suffix option is added to the aux device file name. It can be used
>to identify the corresponding MST device.
I like this idea, but I think there may be a better way that we can do this.
Using /dev/nvme* as an example, we have the standard dev paths (/dev/nvme0,
/dev/nvme0n1, etc.). But we can also access them through /dev/disk/by-
{id,label,partlabel,partuuid,path,uuid}.
So what if we added something similar for aux devices? We start off with the
standard /dev/drm_dp_aux*, then provide more descriptive symlinks and
directories:
(feel free to come up with better naming then this if you can)
/dev/drm_dp_aux/card0-DP-1 -> /dev/drm_dp_aux1
/dev/drm_dp_aux/card0-DP-2 -> /dev/drm_dp_aux2
etc.
>
> Signed-off-by: Leo Li
> ---
> drivers/gpu/drm/drm_crtc_helper_internal.h | 5 +++--
> drivers/gpu/drm/drm_dp_aux_dev.c | 8
> drivers/gpu/drm/drm_dp_helper.c| 2 +-
> 3 files changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_crtc_helper_internal.h
> b/drivers/gpu/drm/drm_crtc_helper_internal.h
> index b5ac158..9f0907b 100644
> --- a/drivers/gpu/drm/drm_crtc_helper_internal.h
> +++ b/drivers/gpu/drm/drm_crtc_helper_internal.h
> @@ -46,7 +46,7 @@ static inline int drm_fb_helper_modinit(void)
> #ifdef CONFIG_DRM_DP_AUX_CHARDEV
> int drm_dp_aux_dev_init(void);
> void drm_dp_aux_dev_exit(void);
> -int drm_dp_aux_register_devnode(struct drm_dp_aux *aux);
> +int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char
> *suffix);
> void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux);
> #else
> static inline int drm_dp_aux_dev_init(void)
> @@ -58,7 +58,8 @@ static inline void drm_dp_aux_dev_exit(void)
> {
> }
>
> -static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
> +static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux,
> + const char *suffix)
> {
> return 0;
> }
> diff --git a/drivers/gpu/drm/drm_dp_aux_dev.c
> b/drivers/gpu/drm/drm_dp_aux_dev.c
> index 0e4f25d..2310a67 100644
> --- a/drivers/gpu/drm/drm_dp_aux_dev.c
> +++ b/drivers/gpu/drm/drm_dp_aux_dev.c
> @@ -80,8 +80,7 @@ static struct drm_dp_aux_dev *alloc_drm_dp_aux_dev(struct
> drm_dp_aux *aux)
> kref_init(_dev->refcount);
>
> mutex_lock(_idr_mutex);
> - index = idr_alloc_cyclic(_idr, aux_dev, 0, DRM_AUX_MINORS,
> - GFP_KERNEL);
> + index = idr_alloc(_idr, aux_dev, 0, DRM_AUX_MINORS, GFP_KERNEL);
> mutex_unlock(_idr_mutex);
> if (index < 0) {
> kfree(aux_dev);
> @@ -290,7 +289,7 @@ void drm_dp_aux_unregister_devnode(struct drm_dp_aux
> *aux)
> kref_put(_dev->refcount, release_drm_dp_aux_dev);
> }
>
> -int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
> +int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char *suffix)
> {
> struct drm_dp_aux_dev *aux_dev;
> int res;
> @@ -301,7 +300,8 @@ int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
>
> aux_dev->dev = device_create(drm_dp_aux_dev_class, aux->dev,
>MKDEV(drm_dev_major, aux_dev->index),
> NULL,
> - "drm_dp_aux%d", aux_dev->index);
> + "drm_dp_aux%d%s", aux_dev->index,
> + suffix ? suffix : "");
> if (IS_ERR(aux_dev->dev)) {
> res = PTR_ERR(aux_dev->dev);
> aux_dev->dev = NULL;
> diff --git a/drivers/gpu/drm/drm_dp_helper.c
> b/drivers/gpu/drm/drm_dp_helper.c
> index e2266ac..13f1005 100644
> --- a/drivers/gpu/drm/drm_dp_helper.c
> +++ b/drivers/gpu/drm/drm_dp_helper.c
> @@ -1143,7 +1143,7 @@ int drm_dp_aux_register(struct drm_dp_aux *aux)
> strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
> sizeof(aux->ddc.name));
>
> - ret = drm_dp_aux_register_devnode(aux);
> + ret = drm_dp_aux_register_devnode(aux, NULL);
> if (ret)
> return ret;
>
--
Cheers,
Lyude Paul
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[PATCH 1/2] drm/dp_aux: Use non-cyclic idr, add suffix option for aux device
From: Leo Li
In preparation for adding aux devices for DP MST:
1. A non-cyclic idr is used for the device minor version. That way,
hotplug cycling MST devices won't needlessly increment the minor
version index.
2. A suffix option is added to the aux device file name. It can be used
to identify the corresponding MST device.
Signed-off-by: Leo Li
---
drivers/gpu/drm/drm_crtc_helper_internal.h | 5 +++--
drivers/gpu/drm/drm_dp_aux_dev.c | 8
drivers/gpu/drm/drm_dp_helper.c| 2 +-
3 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/drm_crtc_helper_internal.h
b/drivers/gpu/drm/drm_crtc_helper_internal.h
index b5ac158..9f0907b 100644
--- a/drivers/gpu/drm/drm_crtc_helper_internal.h
+++ b/drivers/gpu/drm/drm_crtc_helper_internal.h
@@ -46,7 +46,7 @@ static inline int drm_fb_helper_modinit(void)
#ifdef CONFIG_DRM_DP_AUX_CHARDEV
int drm_dp_aux_dev_init(void);
void drm_dp_aux_dev_exit(void);
-int drm_dp_aux_register_devnode(struct drm_dp_aux *aux);
+int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char *suffix);
void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux);
#else
static inline int drm_dp_aux_dev_init(void)
@@ -58,7 +58,8 @@ static inline void drm_dp_aux_dev_exit(void)
{
}
-static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
+static inline int drm_dp_aux_register_devnode(struct drm_dp_aux *aux,
+ const char *suffix)
{
return 0;
}
diff --git a/drivers/gpu/drm/drm_dp_aux_dev.c b/drivers/gpu/drm/drm_dp_aux_dev.c
index 0e4f25d..2310a67 100644
--- a/drivers/gpu/drm/drm_dp_aux_dev.c
+++ b/drivers/gpu/drm/drm_dp_aux_dev.c
@@ -80,8 +80,7 @@ static struct drm_dp_aux_dev *alloc_drm_dp_aux_dev(struct
drm_dp_aux *aux)
kref_init(_dev->refcount);
mutex_lock(_idr_mutex);
- index = idr_alloc_cyclic(_idr, aux_dev, 0, DRM_AUX_MINORS,
-GFP_KERNEL);
+ index = idr_alloc(_idr, aux_dev, 0, DRM_AUX_MINORS, GFP_KERNEL);
mutex_unlock(_idr_mutex);
if (index < 0) {
kfree(aux_dev);
@@ -290,7 +289,7 @@ void drm_dp_aux_unregister_devnode(struct drm_dp_aux *aux)
kref_put(_dev->refcount, release_drm_dp_aux_dev);
}
-int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
+int drm_dp_aux_register_devnode(struct drm_dp_aux *aux, const char *suffix)
{
struct drm_dp_aux_dev *aux_dev;
int res;
@@ -301,7 +300,8 @@ int drm_dp_aux_register_devnode(struct drm_dp_aux *aux)
aux_dev->dev = device_create(drm_dp_aux_dev_class, aux->dev,
MKDEV(drm_dev_major, aux_dev->index), NULL,
-"drm_dp_aux%d", aux_dev->index);
+"drm_dp_aux%d%s", aux_dev->index,
+suffix ? suffix : "");
if (IS_ERR(aux_dev->dev)) {
res = PTR_ERR(aux_dev->dev);
aux_dev->dev = NULL;
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index e2266ac..13f1005 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -1143,7 +1143,7 @@ int drm_dp_aux_register(struct drm_dp_aux *aux)
strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
sizeof(aux->ddc.name));
- ret = drm_dp_aux_register_devnode(aux);
+ ret = drm_dp_aux_register_devnode(aux, NULL);
if (ret)
return ret;
--
2.7.4
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