[Mesa-dev] Change in Mesa triggers bug in Firefox Nightly with WebRender on old AMD hardware

[Viktor Jaegerskuepper]

Dave Airlie:
> On Wed, 1 May 2019 at 12:34, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>>
>> On Tue, Apr 30, 2019 at 10:42 AM Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>>>
>>> On Tue, Apr 30, 2019 at 2:48 AM Dave Airlie <airlied at gmail.com> wrote:
>>>>
>>>> On Tue, 30 Apr 2019 at 08:47, Dave Airlie <airlied at gmail.com> wrote:
>>>>>
>>>>> On Tue, 30 Apr 2019 at 08:42, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>>>>>>
>>>>>> Thing is, I think that would not be enough - with the "recent" (like
>>>>>> past 2 years) CSO/state change detection changes, I think that you can
>>>>>> end up with no sampler set for a buffer view. Perhaps someone with the
>>>>>> hw can investigate what goes wrong?
>>>>>
>>>>> I'm trying to get a live r600/700 machine, I plugged in my rv635 and
>>>>> rv740 gpus, and they both seemed toast, I've got an rv635 laptop I'll
>>>>> try and get up to date.
>>>>
>>>> I've found a working rv770 and reproduced it here. This isn't an
>>>> indication I'll get to fix it soon, but I will try.
>>>
>>> When I was debugging this issue on nouveau (and trying to nail down
>>> specifically what didn't work and what was required to make it work),
>>> I found that using a gallium test to debug this made the issues at
>>> hand quite obvious, and I didn't have to worry about how to force the
>>> st to assign mappings here or there for views or samplers. I'm not
>>> sure if I still have those left over, but I'll have a look tonight.
>>> They're also not terribly difficult to write.
>>
>> In case it's helpful:
>> https://people.freedesktop.org/~imirkin/tbo-tex.c which fits together
>> with the other gallium/tests/trivial ones.
>>
>> I think there were associated Makefile.am changes, but with the
>> removal of autoconf, I probably lost the local changes.
>>
>> In its current form, it doesn't create a sampler, but you can see how
>> trivial/quad-tex.c does it if you want to play around with having
>> samplers around. You might also have to use PIPE_FORMAT_R8G8B8A8_UNORM
>> instead of the BGRA variant for the view's format (iirc r600 has some
>> limitations around swizzling and buffer textures).
>>
> 
> Thanks for test, but I ended up installing firefox and watching the
> pain, then found it by accident.
> 
> https://patchwork.freedesktop.org/patch/302675/
> 
> For Viktor to test.

Tested with RV770, the patch fixes the bug for Firefox Beta and Nightly.

So was this really a bug in the old r600 code or is the patch a
workaround for a Firefox/WebRender bug?

Thanks,
Viktor