[Mesa-dev] [RFC PATCH] dri3: Sync after buffer swaps with glXSwapBuffers

[Eric Anholt]

Thomas Hellstrom <thellstrom at vmware.com> writes:

> Applications calling glXSwapBuffers should be able to expect that any X
> rendering submitted after the call to glXSwapBuffers returns should be ordered
> with respect to the glXSwapBuffers call. (For example piglit reading out from
> a window). This appears not to be the case at least with the current server
> side present extension implementation.
>
> Fixes piglit glx-multithread-texture on svga/vmwgfx.

I don't believe that's true.  From the 1.4 spec:

"glXSwapBuffers is in the X stream if and only if the display and
drawable are not those belonging to the calling thread’s current
context;"

So if you want to sync X rendering after swap, you need glXWaitForGL().
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