OpenGL in fullscreen is choppy since: commit 8369166349c92a20d9a2e7d0256e63f66fe2682b Author: Chris Wilson <chris@chris-wilson.co.uk> Date: Wed Jun 4 08:29:51 2014 +0100 sna/dri2: Enable immediate buffer exchanges The primary benefit of this is avoid the extra blit when using a compositor and instead propagate the compositor flip on the frontbuffer to the scanout, or equivalently allows a fullscreen game to flip onto the scanout without intervention by TearFree. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> How to reproduce: 1. Download http://rghost.ru/56512098. This is 60 fps video 2. mplayer -vo gl output.mp4 or mpv --vo opengl output.mp4 3. Watch video in windowed mode. It should play very smooth 4. Run mplayer/mpv again. Press "f" to go fullscreen Expected result: Video in fullscreen is as smooth as in windowed mode Actual result: Video is choppy Additional information: I'm running ArchLinux with latest KDE and KWin. It happens only with compositing on and does not have any correlation with vsync. I'm not using TearFree driver option.
Kwin makes a buggy micro-optimisation: diff --git a/kwin/libkwineffects/kwinglplatform.cpp b/kwin/libkwineffects/kwinglplatform.cpp index ae2f459..c41b9df 100644 --- a/kwin/libkwineffects/kwinglplatform.cpp +++ b/kwin/libkwineffects/kwinglplatform.cpp @@ -808,7 +808,6 @@ void GLPlatform::detect(OpenGLPlatformInterface platformInterface) m_supportsGLSL = false; m_limitedGLSL = m_supportsGLSL && m_chipClass < I965; - m_looseBinding = true; if (m_chipClass < I915) { m_recommendedCompositor = XRenderCompositing;
(In reply to comment #1) Thanks! Filled bug to KDE bugtracker https://bugs.kde.org/show_bug.cgi?id=336589
*** Bug 80428 has been marked as a duplicate of this bug. ***
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