glamor woes with nouveau

[Olivier Fourdan]

On 18 January 2017 at 10:10, Olivier Fourdan <fourdan at gmail.com> wrote:
> Hi Eric
>
> On 17 January 2017 at 21:25, Eric Anholt <eric at anholt.net> wrote:
>>
>> It sounds like nouveau is failing at the getteximage/texsubimage cycle
>> in the fallback path.  X sometimes finds bugs in Mesa than our testcases
>> miss, because it frequently reads/writes subsets of a texture.  In
>> comparison, testcases tend to use solid colors, window system
>> renderbuffers instead of textures, and the whole renderbuffer instead of
>> a subset.
>>
>> I'd recommend getting an apitrace of the rendering under Xephyr -glamor,
>> if possible.   Then you can use apitrace to dump images of each draw
>> call on both intel and nouveau, and identify which draw call/texture
>> upload was the one that failed.
>
> This is where it gets even more confusing, I cannot reproduce the
> issue using "Xephyr -glamor"...  Not even with Xephyr running in
> Xwayland.

And by that I mean, rendering is fine and I don't get the errors
"glamor_composite_choose_shader: Unsupported source picture format"
when using "Xephyr -glamor"

> I can reproduce on Xwayland though (I mean, running another Xwayland
> server in a Wayland session), I can capture an apitrace of that, but
> the apitrace looks incomplete and cannot be replayed (no context).
>
> Cheers,
> Olivier