[Mesa-dev] [PATCH v3] glx/dri3: Use a separate xcb connection for Present events

[Axel Davy]

Le 20/04/2015 07:08, Axel Davy a écrit :
> Le 20/04/2015 03:58, Michel Dänzer a écrit :
>> On 19.04.2015 06:17, Axel Davy wrote:
>>> v3: put the xcb_connection in dri3_screen, instead of dri3_context
>> What's the rationale for that? Couldn't that result in the same
>> xcb_connection being used in several threads again (for several GLX
>> contexts using the same screen)?
>>
>>
>
> One way is to have one xcb_connection to listen to present events, 
> which can be in dri3_screen, while we could have a second 
> xcb_connection in dri3_context, that would be used to send the present 
> requests.
> _______________________________________________
>
The GLX spec seems to allow having several threads rendering to the same 
drawable, and suggests only one thread does the glxSwapBuffers call.

Thus I think I have to do similar to what is done in gallium nine that is:
. A mutex to prevent the drawable structure fields related to Present
. A system with mutexes to make only one thread dispatch present events 
at a time
. One connection to dispatch the present events, the other one for 
sending them. (That way you can send while one thread is waiting to 
dispatch).

Axel