[Mesa-dev] DRI2 pixmap swapping

Thomas Hellstrom thellstrom at vmware.com
Wed Dec 7 00:18:22 PST 2011

On 12/06/2011 07:58 PM, Eric Anholt wrote:
> On Tue, 6 Dec 2011 16:44:30 +0000, Dave Airlie<airlied at gmail.com>  wrote:
>> Hi,
>> So GLX has a rule about not swapping pixmaps, and I've been trying to
>> track down why with DRI2 my driver gets requests for swapping pixmaps
>> (piglit glx-swap-pixmap test).
>> So it appears in the DRI2 buffer swap case, we bypass the GLX protocol
>> and use the DRI2SwapBuffers protocol, now nowhere on the X server
>> checks that the swap is for a Window and not a pixmap, so it happily
>> ends up calling into my driver and executing a page flip and messing
>> up my screen. So the question is whether
>> So is DRI2 pixmap swapping is something someone thought should be
>> legal despite GLX or is it just an oversight? if so trivial patch is
>> attached.
> I wrote a pretty similar patch
> (<1306964943-15228-1-git-send-email-eric at anholt.net>), which Ville
> complained about because he thought client-side should be checking for
> pixmap/single-buffered instead.  I disagree, so I'm in favor of this
> change.
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I have a feeling, since dri2 is not strictly restricted to GLX, whether 
this should really be
implemented in the glx code before calling into dri2? Otoh that would 
mean the server side
would need to be able to handle the case anyway.


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