Comment # 7
on bug 98784
from Samuel Pitoiset
Can you try with LIBGL_DRI3_DISABLE=1 ? This will use DRI2 and it should fix the flickering. After bisecting, the first bad commit seems to be: commit d3d33918c79d9e87aedaf6f70ed39f75eed262a0 Author: Michel Dänzer <michel.daenzer@amd.com> Date: Wed Aug 17 17:02:04 2016 +0900 loader/dri3: Overhaul dri3_update_num_back Always use 3 buffers when flipping. With only 2 buffers, we have to wait for a flip to complete (which takes non-0 time even with asynchronous flips) before we can start working on the next frame. We were previously only using 2 buffers for flipping if the X server supports asynchronous flips, even when we're not using asynchronous flips. This could result in bad performance (the referenced bug report is an extreme case, where the inter-frame stalls were preventing the GPU from reaching its maximum clocks). I couldn't measure any performance boost using 4 buffers with flipping. Performance actually seemed to go down slightly, but that might have been just noise. Without flipping, a single back buffer is enough for swap interval 0, but we need to use 2 back buffers when the swap interval is non-0, otherwise we have to wait for the swap interval to pass before we can start working on the next frame. This condition was previously reversed. Cc: "12.0 11.2" <mesa-stable@lists.freedesktop.org> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97260 Reviewed-by: Frank Binns <frank.binns@imgtec.com> Reviewed-by: Eric Anholt <eric@anholt.net> (cherry picked from commit 1e3218bc5ba2b739261f0c0bacf4eb662d377236) Squashed with commit: loader/dri3: Always use at least two back buffers This can make a significant difference for performance with some extreme test cases such as vblank_mode=0 glxgears. Fixes: 1e3218bc5ba2 ("loader/dri3: Overhaul dri3_update_num_back") Cc: "12.0 11.2" <mesa-stable@lists.freedesktop.org> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97549 Reviewed-by: Jason Ekstrand <jason@jlekstrand.net> Tested-by: Dieter Nützel <Dieter@nuetzel-hh.de> (cherry picked from commit dc3bb5db8c81e7f08ae12ea5d3ee999e2afcbfd1) :040000 040000 aa5cf86f1e98d023f9539a6a15654fd9754101a2 fb92ad057feeb3fbff38d808c71c7e5e1cead9af M src
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