Bug 352405

Summary:	Window borders glitches when blur is active
Product:	[Plasma] kwin	Reporter:	DrHouse <housegregory299>
Component:	effects-window-management	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UNMAINTAINED
Severity:	normal
Priority:	NOR
Version First Reported In:	4.11.16
Target Milestone:	---
Platform:	Gentoo Packages
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:
Attachments:	Glitch on window border Kwin support info

Description DrHouse 2015-09-07 22:25:12 UTC

Hi!
Window border glitches appears after long time in kde4 session. I tried to change engine to native/raster, set openGL to lower versions, but nothing of these helped me.
I noticed that weird glitches disappearing when I disable Blur effect in Desktop Effects.
I use x11-drivers/nvidia-drivers-355.06-r1. I'll attach screenshoot that describes about that bug more understandable

Reproducible: Always

Steps to Reproduce:
1. Login to kde4-session and enable Blur effect 
2. Working with session as usually
3. Disable blur in Effects tab of Desktop effects, when you'll notice mentioned glitches
4. Enable it again and when opening another app (e.g. Dolphin) you can see glitch above at upper border of window.


Expected Results:  
These glitches shouldn't be happened when blur is active

https://paste.kde.org/psfm7ibhl
Kwin Support Information

http://i.imgur.com/De98vlE.png
Screenshot that describes the problem

Comment 1 DrHouse 2015-09-07 22:28:04 UTC

Created attachment 94463 [details]
Glitch on window border

Comment 2 DrHouse 2015-09-07 22:28:46 UTC

Created attachment 94464 [details]
Kwin support info

Comment 3 Martin Flöser 2015-09-08 06:21:12 UTC

Thank you for your bug report. Unfortunately you reported against a 4.x version which is nowadays unsupported. Given that your bug is impossible to be investigated and even fixed. Too many things have changed since the version you use.

Please test again with a recent version of KWin (e.g. 5.4). If the problem is still visible please reopen.

If you need user support for trying to mitigate the problem, please use forum.kde.org.

Comment 4 Thomas Lübking 2015-09-08 07:32:26 UTC

This looks like junk in the shadow texture (while I thought oxygen combined shadow and border)

- Have you tried whether running w/o the blur effect actually makes the issue inreproducible (and the problem isn't simply cleared by reloading the compositor)?

- does the texture junk stay
  a) in position
  b) with the window border
  when
  a) moving the window?
  b) moving another window
      1. on top
      2. below it

- set the tearing prevention to either "only when cheap" or "full scene repaints" so that we stay away from the frontbuffer.

Comment 5 DrHouse 2015-09-09 22:49:05 UTC

(In reply to Thomas Lübking from comment #4)
> This looks like junk in the shadow texture (while I thought oxygen combined
> shadow and border)
> 
> - Have you tried whether running w/o the blur effect actually makes the
> issue inreproducible (and the problem isn't simply cleared by reloading the
> compositor)?
> 
> - does the texture junk stay
>   a) in position
>   b) with the window border
>   when
>   a) moving the window?
>   b) moving another window
>       1. on top
>       2. below it
> 
> - set the tearing prevention to either "only when cheap" or "full scene
> repaints" so that we stay away from the frontbuffer.

Reloading compositor "solves" the problem of blur for short time only. I can't determined definitely what is causing that weird issue.

Comment 6 DrHouse 2015-09-09 23:01:21 UTC

(In reply to Thomas Lübking from comment #4)
> - does the texture junk stay
>   a) in position
>   b) with the window border
>   when
>   a) moving the window?
>   b) moving another window
>       1. on top
>       2. below it
It appears below it or on top, randomly, when I open, minimize or maximize the window, but often it is on top. Yes, junk stay in position with the window border and disappears for short time when I move the window .

Comment 7 Thomas Lübking 2015-09-10 20:19:25 UTC

It will hide during movement because of the wobbly window effect (which should disable blurring)

Seems like some shadow texture gets polluted by blurring (do the artifacts match some blurred region on your screen?) - but I lack any idea "why".

Does
>  after long time in kde4 session
perhaps include suspends to ram (and wake-ups)?