Bug 168467 - kde4 kwin should sync to vblank (motion tearing)
Summary: kde4 kwin should sync to vblank (motion tearing)
Status: RESOLVED WORKSFORME
Alias: None
Product: kwin
Classification: Plasma
Component: general (other bugs)
Version First Reported In: unspecified
Platform: Ubuntu Linux
: NOR wishlist
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2008-08-06 05:01 UTC by Luke
Modified: 2008-08-08 15:23 UTC (History)
0 users

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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