Bug 304984

Summary: Kwin Logout Effect Flicker on Countdown / Updated Regions
Product: [Plasma] kwin Reporter: eric.erfanian
Component: effects-variousAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED DUPLICATE    
Severity: normal    
Priority: NOR    
Version First Reported In: 4.9.0   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description eric.erfanian 2012-08-11 15:58:32 UTC 
The Kwin logout/desaturate effect now works, but countdown/updated areas causes the effect to flicker in that region.

So, for example, CPU usage bars in Conky or the shutdown countdown dialogue on the logout box flickers while the screen is dimmed. Frequently, the region will jump between the new number and the previously displayed number.

Appears similar to https://bugs.kde.org/show_bug.cgi?id=277409

Reproducible: Always

Steps to Reproduce:
1. Enable the logout effect.
Run some sort of output that is updated frequently, e.g.:
2. Set a screenshot delay to take a picture of the logout dialog (Countdown will be at the top of the screen) OR
3. Run Conky in the background
Actual Results:  
4. Areas where there is active updating will flicker and jump back to the previous number in the countdown. CPU usage spikes in Conky.

Expected Results:  
4. No flicker should occur, only smooth transitions in the countdown dialogue.

Using OpenGL and Raster. Open GL 2 Shaders is checked in Desktop Effects.
Comment 1 Thomas Lübking 2012-08-11 16:12:42 UTC 
because of glSwapInterval ./. page flipping.
nvidia gpu?
Comment 2 eric.erfanian 2012-08-11 16:16:26 UTC 
No Nvidia here. Here is the driver I have installed currently:

xf86-video-intel 2.20.3-1 (xorg-drivers xorg) [installed]
    X.org Intel i810/i830/i915/945G/G965+ video drivers

lspci | grep VGA:
00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 07)
Comment 3 Thomas Lübking 2012-08-11 19:33:12 UTC 
Driver / GPU is not crucial but you could have easily turned off page flipping then :-(

The bug is on the Todo list, in doubt we'll just skip glSwapInterval until there's a correct solution.

*** This bug has been marked as a duplicate of bug 304375 ***