Bug 168467

Summary:	kde4 kwin should sync to vblank (motion tearing)
Product:	[Plasma] kwin	Reporter:	Luke <lcampagn>
Component:	general	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED WORKSFORME
Severity:	wishlist
Priority:	NOR
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Ubuntu
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Luke 2008-08-06 05:01:00 UTC

Version:            (using KDE 4.1.0)
Installed from:    Ubuntu Packages

I am using kubuntu Hardy / KDE4.1 on a Lenovo X60 tablet. I have desktop
effects turned on, and everything looks great, very smooth animation,
except: the screen redraw does not synchronize with vblank. I have tried
clicking "Use VSync" in the Effects options, but no change.

The tearing I am seeing is usually pretty subtle. It is most noticeable
when vertical lines are moving horizontally across the screen (ie
dragging windows, panning large photos, etc.). When it is noticeable, it
makes a shimmering/ripply effect that really detracts from the overall
smooth feel of KDE4.

My graphics hardware:
 Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller (rev 03)

Comment 1 Lubos Lunak 2008-08-07 11:42:05 UTC

It does use vsync. However, vsync works only with direct rendering and AIGLX requires indirect rendering. X problem.

Comment 2 Luke 2008-08-08 15:23:46 UTC

I reported this upstream with X.org. Their response:

  --- Comment #1 from Michel D