[Mesa-dev] [PATCH 1/3] vl/dri3: use external texture as back buffers(v4)

[Alex Deucher]

On Tue, Jan 10, 2017 at 4:50 AM, Nayan Deshmukh
<nayan26deshmukh at gmail.com> wrote:
> On Fri, Jan 6, 2017 at 2:20 AM, Andy Furniss <adf.lists at gmail.com> wrote:
>> Christian König wrote:
>>>
>>> Am 04.01.2017 um 18:13 schrieb Nayan Deshmukh:
>>>>
>>>> dri3 allows us to send handle of a texture directly to X
>>>> so this patch allows a state tracker to directly send its
>>>> texture to X to be used as back buffer and avoids extra
>>>> copying
>>>>
>>>> v2: use clip width/height to display a portion of the surface
>>>> v3: remove redundant variables, fix wrapping, rename variables
>>>>      handle vaapi path
>>>> v3.1: we need clip_width/height for every frame so we don't need
>>>>        to maintain it for each buffer instead use a global variable
>>>> v4: In case of single gpu we can cache the buffers as applications
>>>>      use constant number of buffer and we can avoid calls to present
>>>>      extension for every frame
>>>>
>>>> Suggested-by: Leo Liu <leo.liu at amd.com>
>>>> Signed-off-by: Nayan Deshmukh <nayan26deshmukh at gmail.com>
>>>
>>>
>>> Acked-by: Christian König <christian.koenig at amd.com>.
>>>
>>> Andy & Leo did you guys already had a chance to test it? To me it looks
>>> like this should work now.
>>
>>
>> Well there is still the tearing issue from loosing pageflips.
>>
>> Maybe different GPUs don't see this. I can fix by forcing perf but I
>> just tested dal and it's not even fixable running that.
>>
>> I guess that may not count as an issue with these patches as such if
>> xorg/xf86-video-amdgpu can work around, but it's a very noticeable
>> regression until that happens.
>>
>
> That's bad. It should have improved the speed due to less copying involved.
> But it seems there are some problems in the patch. It may be that somehow we
> make calls to present extension on every frame.
>

This is not the fault of your patches.  They reduce the copying
involved with generates less GPU activity which causes the GPU to not
ramp up the clocks as high.  For multi-media especially, we really
need to add a kernel interface to request a minimum clock floor for
specific contexts.

Alex

> Andy you are using dri3 for testing, right?
>
> Leo, did you also experience tearing issues?
>
> Regards,
> Nayan
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