Re: Regression in 5.4 kernel on 32-bit Radeon IBM T40

2020-09-16 Thread Alex Deucher
On Mon, Feb 24, 2020 at 4:20 AM Thomas Backlund  wrote:
>
> Den 09-01-2020 kl. 17:12, skrev Christian König:
> > Hi Christoph,
> >
> > Am 09.01.20 um 15:14 schrieb Christoph Hellwig:
> >> Hi Woody,
> >>
> >> sorry for the late reply, I've been off to a vacation over the holidays.
> >>
> >> On Sat, Dec 14, 2019 at 10:17:15PM -0500, Woody Suwalski wrote:
> >>> Regression in 5.4 kernel on 32-bit Radeon IBM T40
> >>> triggered by
> >>> commit 33b3ad3788aba846fc8b9a065fe2685a0b64f713
> >>> Author: Christoph Hellwig 
> >>> Date:   Thu Aug 15 09:27:00 2019 +0200
> >>>
> >>> Howdy,
> >>> The above patch has triggered a display problem on IBM Thinkpad T40,
> >>> where
> >>> the screen is covered with a lots of random short black horizontal
> >>> lines,
> >>> or distorted letters in X terms.
> >>>
> >>> The culprit seems to be that the dma_get_required_mask() is returning a
> >>> value 0x3fff
> >>> which is smaller than dma_get_mask()0x.That results in
> >>> dma_addressing_limited()==0 in ttm_bo_device(), and using 40-bits dma
> >>> instead of 32-bits.
> >> Which is the intended behavior assuming your system has 1GB of memory.
> >> Does it?
> >
> > Assuming the system doesn't have the 1GB split up somehow crazy over the
> > address space that should indeed work as intended.
> >
> >>
> >>> If I hardcode "1" as the last parameter to ttm_bo_device_init() in
> >>> place of
> >>> a call to dma_addressing_limited(),the problem goes away.
> >> I'll need some help from the drm / radeon / TTM maintainers if there are
> >> any other side effects from not passing the need_dma32 paramters.
> >> Obviously if the device doesn't have more than 32-bits worth of dram and
> >> no DMA offset we can't feed unaddressable memory to the device.
> >> Unfortunately I have a very hard time following the implementation of
> >> the TTM pool if it does anything else in this case.
> >
> > The only other thing which comes to mind is using huge pages. Can you
> > try a kernel with CONFIG_TRANSPARENT_HUGEPAGE disabled?
> >
>
>
> Any progress on this ?
>
> We have a bugreport in Mageia with the hw:
> Dell Inspiron 5100, 32-bit P4 processor, 2GB of RAM, Radeon Mobility
> 7500 (RV200) graphics
>
> that gets display issues too and reverting the offending commit restores
> normal behaviour.
>
> and the same issue is still there with 5.5 series kernels.

Does disabling HIMEM or setting radeon.agpmode=-1 on the kernel
command line in grub fix the issue?

Alex
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Re: Regression in 5.4 kernel on 32-bit Radeon IBM T40

2020-03-15 Thread Thomas Schwinge
-
Mentor Graphics (Deutschland) GmbH, Arnulfstraße 201, 80634 München / Germany
Registergericht München HRB 106955, Geschäftsführer: Thomas Heurung, Alexander 
Walter
--- Begin Message ---
Hi!

Has any progress been made regarding the issue reported here?

Having updated the software (here: Linux kernel), I'm running into the
same issue on my venerable ;-) Thinkpad T42 with:

01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] 
RV200/M7 [Mobility Radeon 7500]

I lack knowledge of the specific graphics hardware/memory interface as
well as Linux kernel graphics/memory stack at that level, but I'll be
happy to try any suggestions, or test patches etc.

On 2020-01-09T21:40:50-0500, Woody Suwalski  wrote:
> Woody Suwalski wrote:
>> Christian König wrote:
>>> Am 09.01.20 um 15:14 schrieb Christoph Hellwig:
>>>> On Sat, Dec 14, 2019 at 10:17:15PM -0500, Woody Suwalski wrote:
>>>>> Regression in 5.4 kernel on 32-bit Radeon IBM T40
>>>>> triggered by
>>>>> commit 33b3ad3788aba846fc8b9a065fe2685a0b64f713
>>>>> Author: Christoph Hellwig 
>>>>> Date:   Thu Aug 15 09:27:00 2019 +0200
>>>>>
>>>>> The above patch has triggered a display problem on IBM Thinkpad 
>>>>> T40, where
>>>>> the screen is covered with a lots of random short black horizontal 
>>>>> lines,
>>>>> or distorted letters in X terms.
>>>>>
>>>>> The culprit seems to be that the dma_get_required_mask() is 
>>>>> returning a
>>>>> value 0x3fff
>>>>> which is smaller than dma_get_mask()0x.That results in
>>>>> dma_addressing_limited()==0 in ttm_bo_device(), and using 40-bits dma
>>>>> instead of 32-bits.
>>>> Which is the intended behavior assuming your system has 1GB of memory.
>>>> Does it?
>>>
>>> Assuming the system doesn't have the 1GB split up somehow crazy over 
>>> the address space that should indeed work as intended.
>>>
>>>>
>>>>> If I hardcode "1" as the last parameter to ttm_bo_device_init() in 
>>>>> place of
>>>>> a call to dma_addressing_limited(),the problem goes away.

I'm confirming that hack "resolves" the issue.

>>>> I'll need some help from the drm / radeon / TTM maintainers if there 
>>>> are
>>>> any other side effects from not passing the need_dma32 paramters.
>>>> Obviously if the device doesn't have more than 32-bits worth of dram 
>>>> and
>>>> no DMA offset we can't feed unaddressable memory to the device.
>>>> Unfortunately I have a very hard time following the implementation of
>>>> the TTM pool if it does anything else in this case.
>>>
>>> The only other thing which comes to mind is using huge pages. Can you 
>>> try a kernel with CONFIG_TRANSPARENT_HUGEPAGE disabled?
>>
>> Yes, the box has 1G of RAM, and unfortunately nope, 
>> TRANSPARENT_HUGEPAGE is not on. I am attaching the .config, maybe you 
>> can find some insanity there... Also - for reference - a minimalistic 
>> patch fixing symptoms (but not addressing the root cause  :-( )
>>
>> I can try to rebuild the kernel with HIGHMEM off, although I am not 
>> optimistic it will change anything. But at least it should simplify 
>> the 1G split...
>>
>> So if you have any other ideas - pls let me know..
>>
> Interesting. Rebuilding the kernel with HIMEM disabled actually solves 
> the display problem. The debug lines show exactly same values for 
> dma_get_required_mask() and dma_get_mask(), yet now it works OK... So 
> what has solved it???

That I have not yet tried.


Grüße
 Thomas


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Re: Regression in 5.4 kernel on 32-bit Radeon IBM T40

2020-02-24 Thread Thomas Backlund

Den 09-01-2020 kl. 17:12, skrev Christian König:

Hi Christoph,

Am 09.01.20 um 15:14 schrieb Christoph Hellwig:

Hi Woody,

sorry for the late reply, I've been off to a vacation over the holidays.

On Sat, Dec 14, 2019 at 10:17:15PM -0500, Woody Suwalski wrote:

Regression in 5.4 kernel on 32-bit Radeon IBM T40
triggered by
commit 33b3ad3788aba846fc8b9a065fe2685a0b64f713
Author: Christoph Hellwig 
Date:   Thu Aug 15 09:27:00 2019 +0200

Howdy,
The above patch has triggered a display problem on IBM Thinkpad T40, 
where
the screen is covered with a lots of random short black horizontal 
lines,

or distorted letters in X terms.

The culprit seems to be that the dma_get_required_mask() is returning a
value 0x3fff
which is smaller than dma_get_mask()0x.That results in
dma_addressing_limited()==0 in ttm_bo_device(), and using 40-bits dma
instead of 32-bits.

Which is the intended behavior assuming your system has 1GB of memory.
Does it?


Assuming the system doesn't have the 1GB split up somehow crazy over the 
address space that should indeed work as intended.




If I hardcode "1" as the last parameter to ttm_bo_device_init() in 
place of

a call to dma_addressing_limited(),the problem goes away.

I'll need some help from the drm / radeon / TTM maintainers if there are
any other side effects from not passing the need_dma32 paramters.
Obviously if the device doesn't have more than 32-bits worth of dram and
no DMA offset we can't feed unaddressable memory to the device.
Unfortunately I have a very hard time following the implementation of
the TTM pool if it does anything else in this case.


The only other thing which comes to mind is using huge pages. Can you 
try a kernel with CONFIG_TRANSPARENT_HUGEPAGE disabled?





Any progress on this ?

We have a bugreport in Mageia with the hw:
Dell Inspiron 5100, 32-bit P4 processor, 2GB of RAM, Radeon Mobility 
7500 (RV200) graphics


that gets display issues too and reverting the offending commit restores 
normal behaviour.


and the same issue is still there with 5.5 series kernels.

--
Thomas
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Re: Regression in 5.4 kernel on 32-bit Radeon IBM T40

2020-01-12 Thread Woody Suwalski

Woody Suwalski wrote:

Christian König wrote:

Hi Christoph,

Am 09.01.20 um 15:14 schrieb Christoph Hellwig:

Hi Woody,

sorry for the late reply, I've been off to a vacation over the 
holidays.


On Sat, Dec 14, 2019 at 10:17:15PM -0500, Woody Suwalski wrote:

Regression in 5.4 kernel on 32-bit Radeon IBM T40
triggered by
commit 33b3ad3788aba846fc8b9a065fe2685a0b64f713
Author: Christoph Hellwig 
Date:   Thu Aug 15 09:27:00 2019 +0200

Howdy,
The above patch has triggered a display problem on IBM Thinkpad 
T40, where
the screen is covered with a lots of random short black horizontal 
lines,

or distorted letters in X terms.

The culprit seems to be that the dma_get_required_mask() is 
returning a

value 0x3fff
which is smaller than dma_get_mask()0x.That results in
dma_addressing_limited()==0 in ttm_bo_device(), and using 40-bits dma
instead of 32-bits.

Which is the intended behavior assuming your system has 1GB of memory.
Does it?


Assuming the system doesn't have the 1GB split up somehow crazy over 
the address space that should indeed work as intended.




If I hardcode "1" as the last parameter to ttm_bo_device_init() in 
place of

a call to dma_addressing_limited(),the problem goes away.
I'll need some help from the drm / radeon / TTM maintainers if there 
are

any other side effects from not passing the need_dma32 paramters.
Obviously if the device doesn't have more than 32-bits worth of dram 
and

no DMA offset we can't feed unaddressable memory to the device.
Unfortunately I have a very hard time following the implementation of
the TTM pool if it does anything else in this case.


The only other thing which comes to mind is using huge pages. Can you 
try a kernel with CONFIG_TRANSPARENT_HUGEPAGE disabled?


Thanks,
Christian.


Happy New Year :-)

Yes, the box has 1G of RAM, and unfortunately nope, 
TRANSPARENT_HUGEPAGE is not on. I am attaching the .config, maybe you 
can find some insanity there... Also - for reference - a minimalistic 
patch fixing symptoms (but not addressing the root cause  :-( )


I can try to rebuild the kernel with HIGHMEM off, although I am not 
optimistic it will change anything. But at least it should simplify 
the 1G split...


So if you have any other ideas - pls let me know..

Thanks, Woody

Interesting. Rebuilding the kernel with HIMEM disabled actually solves 
the display problem. The debug lines show exactly same values for 
dma_get_required_mask() and dma_get_mask(), yet now it works OK... So 
what has solved it???


Woody

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Re: Regression in 5.4 kernel on 32-bit Radeon IBM T40

2020-01-09 Thread Christian König

Hi Christoph,

Am 09.01.20 um 15:14 schrieb Christoph Hellwig:

Hi Woody,

sorry for the late reply, I've been off to a vacation over the holidays.

On Sat, Dec 14, 2019 at 10:17:15PM -0500, Woody Suwalski wrote:

Regression in 5.4 kernel on 32-bit Radeon IBM T40
triggered by
commit 33b3ad3788aba846fc8b9a065fe2685a0b64f713
Author: Christoph Hellwig 
Date:   Thu Aug 15 09:27:00 2019 +0200

Howdy,
The above patch has triggered a display problem on IBM Thinkpad T40, where
the screen is covered with a lots of random short black horizontal lines,
or distorted letters in X terms.

The culprit seems to be that the dma_get_required_mask() is returning a
value 0x3fff
which is smaller than dma_get_mask()0x.That results in
dma_addressing_limited()==0 in ttm_bo_device(), and using 40-bits dma
instead of 32-bits.

Which is the intended behavior assuming your system has 1GB of memory.
Does it?


Assuming the system doesn't have the 1GB split up somehow crazy over the 
address space that should indeed work as intended.





If I hardcode "1" as the last parameter to ttm_bo_device_init() in place of
a call to dma_addressing_limited(),the problem goes away.

I'll need some help from the drm / radeon / TTM maintainers if there are
any other side effects from not passing the need_dma32 paramters.
Obviously if the device doesn't have more than 32-bits worth of dram and
no DMA offset we can't feed unaddressable memory to the device.
Unfortunately I have a very hard time following the implementation of
the TTM pool if it does anything else in this case.


The only other thing which comes to mind is using huge pages. Can you 
try a kernel with CONFIG_TRANSPARENT_HUGEPAGE disabled?


Thanks,
Christian.
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Regression in 5.4 kernel on 32-bit Radeon IBM T40

2019-12-16 Thread Woody Suwalski

Regression in 5.4 kernel on 32-bit Radeon IBM T40
triggered by
commit 33b3ad3788aba846fc8b9a065fe2685a0b64f713
Author: Christoph Hellwig 
Date:   Thu Aug 15 09:27:00 2019 +0200

Howdy,
The above patch has triggered a display problem on IBM Thinkpad T40, 
where the screen is covered with a lots of random short black horizontal 
lines, or distorted letters in X terms.


The culprit seems to be that the dma_get_required_mask() is returning a 
value 0x3fff
which is smaller than dma_get_mask()0x.That results in 
dma_addressing_limited()==0 in ttm_bo_device(), and using 40-bits dma 
instead of 32-bits.


If I hardcode "1" as the last parameter to ttm_bo_device_init() in place 
of a call to dma_addressing_limited(),the problem goes away.


I have added the debug lines starting with "wms:" to the start of 
radeon_ttm_init() and of radeon_device_init()printing the interesting 
variables.

/
[    2.091692] Linux agpgart interface v0.103
[    2.092380] agpgart-intel :00:00.0: Intel 855PM Chipset
[    2.107706] agpgart-intel :00:00.0: AGP aperture is 256M @ 0xd000
[    2.108111] [drm] radeon kernel modesetting enabled.
[    2.108200] radeon :01:00.0: vgaarb: deactivate vga console
[    2.109365] Console: switching to colour dummy device 80x25
*** radeon_device_init()
[    2.110712] wms: radeon_init flags = 0x90003
[    2.110718] [drm] initializing kernel modesetting (RV200 
0x1002:0x4C57 0x1014:0x0530 0x00).

[    2.111220] agpgart-intel :00:00.0: AGP 2.0 bridge
[    2.111233] agpgart-intel :00:00.0: putting AGP V2 device into 1x 
mode

[    2.111265] radeon :01:00.0: putting AGP V2 device into 1x mode
[    2.111286] radeon :01:00.0: GTT: 256M 0xD000 - 0xDFFF
[    2.111295] radeon :01:00.0: VRAM: 128M 0xE000 - 
0xE7FF (32M used)

[    2.111701] [drm] Detected VRAM RAM=128M, BAR=128M
[    2.111704] [drm] RAM width 64bits DDR
*** radeon_ttm_init()
[    2.111706] wms: dma_addressing_limited=0x0
[    2.111709] wms: dma_get_mask=0x, bus_dma_limit=0x0, 
dma_get_required_mask=0x3fff

[    2.115971] [TTM] Zone  kernel: Available graphics memory: 437028 KiB
[    2.115973] [TTM] Zone highmem: Available graphics memory: 510440 KiB

What should be the proper value of these dma variables on the 32-bit system?
How to fix that issue correctly (patches welcomed :-) )Or is the 
platform fubar?


Thanks, Woody


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