[PATCH 3/4] drm/mgag200: Add workaround for HW that does not support 'startadd'

[Thomas Zimmermann]

Hi

Am 04.12.19 um 10:36 schrieb Dave Airlie:
> On Wed, 4 Dec 2019 at 17:30, Thomas Zimmermann <tzimmermann at suse.de> wrote:
>>
>> Hi John
>>
>> Am 03.12.19 um 18:55 schrieb John Donnelly:
>>> Hi ,
>>>
>>> See below ,
>>>
>>>
>>>> On Nov 26, 2019, at 3:50 AM, Thomas Zimmermann <tzimmermann at suse.de> wrote:
>>>>
>>>> Hi
>>>>
>>>> Am 26.11.19 um 10:37 schrieb Daniel Vetter:
>>>>> On Tue, Nov 26, 2019 at 08:25:44AM +0100, Thomas Zimmermann wrote:
>>>>>> There's at least one system that does not interpret the value of
>>>>>> the device's 'startadd' field correctly, which leads to incorrectly
>>>>>> displayed scanout buffers. Always placing the active scanout buffer
>>>>>> at offset 0 works around the problem.
>>>>>>
>>>>>> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
>>>>>> Reported-by: John Donnelly <john.p.donnelly at oracle.com>
>>>>>> Link: https://gitlab.freedesktop.org/drm/misc/issues/7
>>>>>
>>>>> Tested-by: John Donnelly <john.p.donnelly at oracle.com>
>>>>>
>>>>> (Not quite this patch, but pretty much the logic, so counts).
>>>>>
>>>>> Fixes: 81da87f63a1e ("drm: Replace drm_gem_vram_push_to_system() with kunmap + unpin")
>>>>> Cc: <stable at vger.kernel.org> # v5.3+
>>>>>
>>>>> Also you need the stable line on both prep patches too. For next time
>>>>> around,
>>>>>
>>>>> $ dim fixes 81da87f63a1e
>>>>>
>>>>> will generate all the stuff you need, including a good set of suggested
>>>>> Cc: you should have.
>>>>>
>>>>> On the first 3 patches, with all that stuff added:
>>>>>
>>>>> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
>>>>
>>>> Thanks for the review.
>>>>
>>>> Sorry for leaving out some of the tags. I wanted to wait for feedback
>>>> before adding tested-by, fixes, stable. I'll split off patch 4 from the
>>>> series and get 1 to 3 merged ASAP.
>>>>
>>>> Best regards
>>>> Thomas
>>>>
>>>>>
>>>>> Please push these to drm-misc-next-fixes so they get backported as quickly
>>>>> as possible.
>>>>> -Daniel
>>>>>
>>>>>> ---
>>>>>> drivers/gpu/drm/mgag200/mgag200_drv.c | 36 ++++++++++++++++++++++++++-
>>>>>> drivers/gpu/drm/mgag200/mgag200_drv.h |  3 +++
>>>>>> 2 files changed, 38 insertions(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c b/drivers/gpu/drm/mgag200/mgag200_drv.c
>>>>>> index 397f8b0a9af8..d43951caeea0 100644
>>>>>> --- a/drivers/gpu/drm/mgag200/mgag200_drv.c
>>>>>> +++ b/drivers/gpu/drm/mgag200/mgag200_drv.c
>>>>>> @@ -30,6 +30,8 @@ module_param_named(modeset, mgag200_modeset, int, 0400);
>>>>>> static struct drm_driver driver;
>>>>>>
>>>>>> static const struct pci_device_id pciidlist[] = {
>>>>>> +  { PCI_VENDOR_ID_MATROX, 0x522, PCI_VENDOR_ID_SUN, 0x4852, 0, 0,
>>>>>> +          G200_SE_A | MGAG200_FLAG_HW_BUG_NO_STARTADD},
>>>
>>>
>>>
>>> I will have an additional list of vendor IDs (0x4852)  I will provide in a follow up patch shortly .  This fixes only 1 flavor  of server.
>>
>> Thank you for all the testing you do. We can add these ids as necessary.
>>
>> Before, I posted a patch at [1] that prints an internal unique id. The
>> id of your original test machine was 0x2 IIRC.
>>
>> My guess is that the problem might be related to the chip's revision. If
>> you have the option of booting your own kernels on all these machines,
>> could you apply the patch and look for a pattern in these ids? Maybe
>> only revision 0x2 is affected.
>>
> 
> I've got an old bug I never got around to that has a comment from Matrox
> 
> "The issue is reproducible with G200e chip. The device ID is 0x0522."
> 
> so it might be a broader problem than we think.

Did they tell you a subvendor id? John reported that the internal
revision id differs among affected machines. I'm thinking about flagging
either Sun devices or all 0x0522 devices as broken.

Best regards
Thomas

> 
> Dave.
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-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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