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

[Michel Dänzer]

On 10/01/17 06:53 PM, Nayan Deshmukh wrote:
> On Sat, Jan 7, 2017 at 12:42 PM, Michel Dänzer <michel at daenzer.net> wrote:
>> On 06/01/17 05:50 AM, Andy Furniss 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.
>>
>> Somebody should track down why the buffers sent for presentation in this
>> case don't use the same tiling parameters as buffers used for GL via DRI3.
>>
> I can look into this, but I don't know where to look exactly. Can you give some
> pointers to get started.

Looking at src/gallium/auxiliary/vl/vl_winsys_dri3.c and the patches
again, my guess is that it's due to PIPE_BIND_SCANOUT not being set when
creating the buffers that are now being directly sent to the X server
for presentation.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer