mirror of
https://github.com/X11Libre/xserver.git
synced 2026-03-24 05:54:08 +00:00
d4bd39f1a5
It's possible for present_execute_copy to enqueue a vblank even when TearFree is used, specifically when the present_queue_vblank in present_scmd_pixmap fails and the subsequent vblank enqueue in present_execute_copy somehow doesn't. This could happen if the DRM event queue is exhausted when present_queue_vblank is called, but is no longer exhausted by the time present_execute_copy is reached. This exceedingly unlikely chain of events can lead to a vblank getting enqueued a second time by the TearFree machinery in present_execute, which is not good. Although this scenario is very unlikely, prevent it by first checking that the vblank wasn't enqueued by present_execute_copy before attempting to enqueue it for TearFree. Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com> Acked-by: Martin Roukala <martin.roukala@mupuf.org>