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Merge pull request #275 from cmeissl/renderer/v4-workaround-delayed-rendering 

Workaround for screen flickering on drm/kms
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Victor Brekenfeld 2021-05-21 17:26:33 +02:00 committed by GitHub
parent a4f66da69f 26527a131f
commit a9209c7ae0
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1 changed files with 15 additions and 0 deletions
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15
src/backend/renderer/gles2/mod.rs
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@ -1069,6 +1069,21 @@ impl Renderer for Gles2Renderer {
self.make_current()?;
unsafe {
self.gl.Flush();
// We need to wait for the previously submitted GL commands to complete
// or otherwise the buffer could be submitted to the drm surface while
// still writing to the buffer which results in flickering on the screen.
// The proper solution would be to create a fence just before calling
// glFlush that the backend can use to wait for the commands to be finished.
// In case of a drm atomic backend the fence could be supplied by using the
// IN_FENCE_FD property.
// See https://01.org/linuxgraphics/gfx-docs/drm/gpu/drm-kms.html#explicit-fencing-properties for
// the topic on submitting a IN_FENCE_FD and the mesa kmskube example
// https://gitlab.freedesktop.org/mesa/kmscube/-/blob/9f63f359fab1b5d8e862508e4e51c9dfe339ccb0/drm-atomic.c
// especially here
// https://gitlab.freedesktop.org/mesa/kmscube/-/blob/9f63f359fab1b5d8e862508e4e51c9dfe339ccb0/drm-atomic.c#L147
// and here
// https://gitlab.freedesktop.org/mesa/kmscube/-/blob/9f63f359fab1b5d8e862508e4e51c9dfe339ccb0/drm-atomic.c#L235
self.gl.Finish();
self.gl.Disable(ffi::BLEND);
}