[Mesa-dev] [PATCH] vl/dri3: remove the wait before getting back buffer

[Michel Dänzer]

On 2019-03-21 8:10 p.m., Liu, Leo wrote:
> On 2019-03-20 1:56 p.m., Michel Dänzer wrote:
>> On 2019-03-20 4:42 p.m., Liu, Leo wrote:
>>> The wait here is unnecessary since we got a pool of back buffers,
>>> and the wait for swap buffer will happen before the present pixmap,
>>> at the same time the previous back buffer will be put back to pool
>>> for reuse after the check for PresentIdleNotify event
>>>
>>> Signed-off-by: Leo Liu <leo.liu at amd.com>
>>>
>>>   [...]
>>>
>>> @@ -626,13 +621,6 @@ vl_dri3_screen_texture_from_drawable(struct vl_screen *vscreen, void *drawable)
>>>      if (!dri3_set_drawable(scrn, (Drawable)drawable))
>>>         return NULL;
>>>   
>>> -   if (scrn->flushed) {
>>> -      while (scrn->special_event && scrn->recv_sbc < scrn->send_sbc)
>>> -         if (!dri3_wait_present_events(scrn))
>>> -            return NULL;
>>> -   }
>>> -   scrn->flushed = false;
>>> -
>>>      buffer = (scrn->is_pixmap) ?
>>>               dri3_get_front_buffer(scrn) :
>>>               dri3_get_back_buffer(scrn);
>>>
>> Hmm. Is the wait here not necessary before getting a pixmap's front
>> buffer either though? Maybe wait only here for a pixmap, and only in
>> vl_dri3_flush_frontbuffer for a window?
>>
>> Sorry I didn't realize this earlier.
>>
> The pixmap case is used by Totem player, or previous GLX case for MPV 
> player, and the front buffer of the pixmap is a temporary buffer, and 
> later as source for GL to present.
> 
> For pixmap case, there is no need to wait,  and the dri3 present wait 
> before dri3_get_front_buffer() is not get called, because scrn->flushed 
> will never be true, since our presentation flush code is not used by 
> this case.

Makes sense, thanks.

Reviewed-by: Michel Dänzer <michel.daenzer at amd.com>


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