Bug 390187

Summary:	Glitching/session freeze when changing the tearing prevention
Product:	[Plasma] kwin	Reporter:	pbs3141
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED WORKSFORME
Severity:	crash	CC:	jagannathante, justin.zobel, notuxius
Priority:	NOR	Flags:	mgraesslin: Wayland+
Version:	5.12.0
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed In:

Description pbs3141 2018-02-10 01:21:20 UTC

Observed on Intel Ivy Bridge.
Save work first!

1. Change the tearing prevention from "Full screen repaints" to "Automatic" or vice-versa, and Apply.

2. Move some windows around: observe full-screen black flickering, other windows being partially painted over the active window while typing, and general artefacts.

Either
3a. Logout, and confirm with Ok at the logout screen: session freezes with the logout screen stuck on the screen.

Or
3b. Keep triggering the snap animation by snapping a window against a screen edge but not letting go: observe snap animation displays a garbage texture. Continue for about 10 seconds: graphics freezes, cpu goes to 100%, and disk starts swapping.

4. Try to VT switch: nothing happens.

5. Trigger SysRq+I: get a VT, but it is frozen, and a reboot is necessary, even though kernel is responsive.
   (If you are lucky, you may get the SDDM greeter, and you can login again normally.)

Comment 1 Jagannathan Tiruvallur Eachambadi 2018-02-19 18:16:05 UTC

(In reply to pbs3141 from comment #0)
> 1. Change the tearing prevention from "Full screen repaints" to "Automatic"
> or vice-versa, and Apply.
> 
> 2. Move some windows around: observe full-screen black flickering, other
> windows being partially painted over the active window while typing, and
> general artefacts.

Can confirm this. Full scale black flickering happens when there are no maximized windows in the background. General bad artefacts happen either way.
> 
> Either
> 3a. Logout, and confirm with Ok at the logout screen: session freezes with
> the logout screen stuck on the screen.

I was able to logout but kwin crashed with a truncated core dump so no luck.
> 
> Or
> 3b. Keep triggering the snap animation by snapping a window against a screen
> edge but not letting go: observe snap animation displays a garbage texture.
> Continue for about 10 seconds: graphics freezes, cpu goes to 100%, and disk
> starts swapping.

The "garbage texture" is reproducible but cpu remained quiet.

> 4. Try to VT switch: nothing happens.
> 
> 5. Trigger SysRq+I: get a VT, but it is frozen, and a reboot is necessary,
> even though kernel is responsive.
>    (If you are lucky, you may get the SDDM greeter, and you can login again
> normally.)

This was not reproducible. It is probably specific to your hardware. Please mark the bug confirmed.

Comment 2 Alexander Mentyu 2018-07-03 15:05:12 UTC

Can sometimes reproduce garbage animations after changing tearing prevention - but where rarely - possible after visiting some System Settings modules

Cannot reproduce session freeze 

Plasma: 5.13.2
Apps: 18.04.2
Frameworks: 5.47.0
Qt: 5.11.1
Kernel: 4.18.0-1-MANJARO
OS: Netrunner Rolling
Video: Intel 4400
Driver: xf86-video-intel 1:2.99.917+831+ge7bfc906-1
Mesa 3D: 18.1.3
Screen: 1600x900
Xorg: 1.20
Wayland: 1.15.0-1
Wayland Protocols: 1.14-1

Comment 3 Justin Zobel 2020-12-07 04:13:05 UTC

Thank you for the report.

As it has been a while since this was reported, can you please test and confirm if this issue is still occurring or if this bug report can be marked as resolved.

I have set the bug status to "needsinfo" pending your response, please change back to "reported" or "resolved/worksforme" when you respond, thank you.