On Wed, May 21, 2014 at 08:53:18AM -0700, Jamey Sharp wrote: > UXA was reporting page-flip completion as soon as the flip was scheduled > with the kernel, instead of waiting for the kernel to indicate that the > flip had actually completed. > > Moving the DRI2SwapComplete call to the right place fixes all of our > Piglit tests for OML_sync_control when run on xf86-video-intel/UXA, > aside from a bit of difficult-to-reproduce flakiness when using a > divisor > 1. > > This also eliminates a compile-time and run-time warning when built > against an xserver with "Warn on DRI2SwapComplete with constant UST/MSC" > applied. > > v2: The drawable may have disappeared by the time the flip completes. > Don't try to report swap completion in that case. > > Signed-off-by: Jamey Sharp <jamey@xxxxxxxxxxx> > Cc: Theo Hill <Theo0x48@xxxxxxxxx> > Cc: Eric Anholt <eric@xxxxxxxxxx> > Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > --- > > I can experimentally confirm Chris' claim that this patch causes > SwapBuffers to block once one swap is already outstanding, giving > double-buffering behavior rather than the desired triple-buffering. > > However, it only has an effect for full-screen windows, and only when > not running under a compositor. > > - If the window is not full-screen, UXA is already only double-buffered. > - If full-screen, UXA is usually triple-buffered, but not reliably. > - If run under a compositor, either the compositor crashes during my > test, or it still appears to be triple-buffered even with this patch. > > If you want triple-buffering, NAK'ing this patch is clearly not the way > to get it, since the driver already doesn't do it reliably. > > Please merge this patch, which fixes two spec violations that make > OML_sync_control unusable; and if you're concerned about uncomposited > triple-buffering in UXA, please find a less awful way to get it. Why not just change the default to double buffering? Or fix it correctly? -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
