Bug 328071

Summary: Blur effect produces tearing when using plasma
Product: [Plasma] kwin Reporter: Marc <marcwallington>
Component: effects-window-managementAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED DUPLICATE    
Severity: normal    
Priority: NOR    
Version: 4.11.3   
Target Milestone: ---   
Platform: Kubuntu   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:

Description Marc 2013-11-25 17:00:21 UTC 
If I enable Blur effect and I try to use Takeoff (for example) tearing will appear. It also happens when I use the Calendar and the Network Manager. I'm using Kubuntu 13.10, KDE 4.11.3 and OpengGL 3.1 (raster).

It isn't probably a hardware problem because in KDE 4.10.X it worked very well without any tearing, anyway I'm using the i915 driver and my graphic card is an IntelHD 3000.

This bug is also happening on another computer that I have (Sony Vaio) with IntelHD 4000 graphics, also in Kubuntu 13.10, KDE 4.11.3 and OpenGL 3.1 so for me it's always reproducible.

Thanks

Reproducible: Always

Steps to Reproduce:
1. Activate Blur Effect
2. Use Plasma (i.e Takeoff)
Actual Results:  
Tearing appears, the screen will tear.

Expected Results:  
It should work fluid and not produce the well known tearing effect.

It happens in my two computers and wasn't happening in KDE 4.10.X so It may be a software problem/bug or something.
Comment 1 Thomas Lübking 2013-11-25 17:09:43 UTC 
run "kcmshell4 kwincompositing", on the second tab, filter for blur and check the configuration. is caching enabled?
Comment 2 Marc 2013-11-25 22:45:08 UTC 
(In reply to comment #1)
> run "kcmshell4 kwincompositing", on the second tab, filter for blur and
> check the configuration. is caching enabled?

Yes it was enabled. I disabled it and now it works like a charm! Should this "bug" be closed? my problem is solved but the behaviour shouldn't have tearing regardless of the configuration, right? (I don't know what caching actually means).

Thanks
Comment 3 Thomas Lübking 2013-11-25 22:49:29 UTC 
(In reply to comment #2)
> the behaviour shouldn't have tearing regardless of the configuration, right?

No, unfortunately it's not a trivial bug.
See dupe.

FYI: "tearing" is usually sth. different and refers to old and new frames on different parts of the screen.

*** This bug has been marked as a duplicate of bug 307112 ***