Bug 428467

Summary:	Plasma freezes
Product:	[Plasma] kwin	Reporter:	krzmbrzl
Component:	general	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	major	CC:	nate, plasma-bugs-null
Priority:	NOR
Version First Reported In:	5.20.2
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description krzmbrzl 2020-10-30 10:50:32 UTC

SUMMARY
The complete UI freezes and the computer has to be reset by holding down the power button. No keyboard or mouse input seems to work (so switching to a different TTY is not possible either).

STEPS TO REPRODUCE
I have not yet found a way to reproduce this. It happens a couple of times every day though. It seems like using KDE-specific windows (e.g. widgets, audo volume settings, ...) increases the likelihood of it happening, but this is of course rather vague.

SOFTWARE/OS VERSIONS
Operating System: KDE neon 5.20
KDE Plasma Version: 5.20.2
KDE Frameworks Version: 5.75.0
Qt Version: 5.15.0
Kernel Version: 5.4.0-52-generic
OS Type: 64-bit
Processors: 8 × Intel® Core™ i7-4770 CPU @ 3.40GHz
Memory: 7,7 GiB of RAM
Graphics Processor: NVE4

ADDITIONAL INFORMATION
I used to run KDE Neon on a laptop without ever seeing such an issue. I should note though that the version never ran the 5.20 version. Instead it was running 5.19 when I used it for the last time.

Therefore my suspicion is that this might be a bug that was introduced in 5.20.

Another possibility could also be that the problem is hardware-related as the computer I am seeing the issues on is not the beforementioned laptop.

The freeze is happening on a setup in which I am using 2 monitors (2x 1920x1080). One is connected via HDMI and one via DVI.

IMPORTANT
When the freeze is happening, it seems to really only be the UI that freezes. If I e.g. have a music player running (Clementine) while this happens, the music continues to play.
Furthermore the mouse input freezes only after everything else. So usually I notice that the UI seems to be frozen but I am still able to move my mouse for a few seconds. The mouse input seems to also freeze as soon as the cursor would cross the border of my 2 monitors (e.g. it freezes before switching to the other screen).

QUESTION
What can I do to try to help find out what the cause of this freeze is? Are there some log files that I should inspect (before and) after this has happened again?

Comment 1 Nate Graham 2020-10-30 14:40:49 UTC

If app windows are affected too, it's more likely in KWin.

Comment 2 krzmbrzl 2020-10-30 16:15:16 UTC

It just happened again and the mouse simply froze at a random position on the screen (and not on the border between the screens).

It does seem however that the windows freeze at some point but the mouse is only affected after having moved (clicked?) after the windows have frozen. From then on its a couple of seconds and then the mouse is dead as well.

Comment 3 2wxsy58236r3 2020-10-31 10:31:39 UTC

If you are using an NVIDIA GPU, can you please try switching between the proprietary (NVIDIA) and open-source (Nouveau) drivers?

Comment 4 krzmbrzl 2020-10-31 15:24:21 UTC

Okay I will try out nividia's drivers (was using the nouveau ones before). I will report back how it turned out in a couple of days.

Comment 5 krzmbrzl 2020-11-04 07:06:43 UTC

So I have been using the proprietary nvidia drivers for the last couple of days and the only freezes I encountered happened when I compiled some code and ran out of memory (which seems to be unrelated to the original issue).

So I guess this was a driver issue after all. Thanks for the support :)