Bug 361185

Summary:	Tearing on X11 with EGL
Product:	[Plasma] kwin	Reporter:	equeim
Component:	egl	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED INTENTIONAL
Severity:	normal
Priority:	NOR
Version First Reported In:	5.6.1
Target Milestone:	---
Platform:	Gentoo Packages
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description equeim 2016-03-30 13:23:50 UTC

VSync works fine with GLX, but not with EGL.
I use Gentoo ~amd64. media-libs/mesa-11.1.2 with radeonsi.
x11-base/xorg-server-1.18.1 and x11-drivers/xf86-video-ati-7.6.1_p20160324.
kde-plasma/kwin-5.6.1

Reproducible: Always

Comment 1 Martin Flöser 2016-04-01 13:28:35 UTC

Then please use GLX.

Comment 2 Thomas Lübking 2016-04-01 14:41:58 UTC

wild guess: no subpost, thus EGL_BUFFER_PRESERVED, thus no flipping, thus tearing (cause the swap isn't fast enough for the vblank time)

if you enable kwin debug output and start it from konsole, you should get a line like
   "EGL implementation and surface support eglPostSubBufferNV, let's use it"