7mo ago

KDE Plasma 6 reboots on video playback

Since about Plasma 6 onward I've been getting system restarts when attempting to play back video files and/or seek through them.

The system will crash and reboot when:

Attempting to play any video with an mp4 container (mpv and vlc tested)
Attempting to seek with the mouse while playing most videos (mp4 and matroska)
Scrolling too fast in a file manager
Clicking and dragging to resize various windows (terminal, browsers, etc)

The system performs fine when:

Playing videos in a webm container
Playing videos in software like avidemux, kdenlive, gwenview, etc.
Streaming video in a web browser

The issue has persisted through these toubleshooting measures:

Update to latest BIOS firmware
Switching between Wayland and X11
Substitution of the PSU to a brand new unit

My assumption so far is that it's not hardware related. Currently I suspect it's Plasma. Below is the journal output of records around one such crash time of 5.19-5.20pm:

Suggestions for next steps would be welcome. Is it worth considering a rollback to the previous/older Plasma versions? Assuming Plasma doesn't like my DAC or keyboard or whatever, is it worth substituting or removing USB devices?

6 comments

Try booting to a live ISO. See if it still happens there,
Also you can install a second DE and see if it still happens.

Yes, try without certain devices plugged into USB. Dunno why your keyboard was in the dump, but unplugging a USB peripheral is much easier to test than rolling back software and trying to verify from there.
Also, I saw an error that mentioned a Pixel 5. Are you trying to open video from a connected Pixel device or something?

So get this: I tested a live USB, and initially any video playback caused the crash, then 4k video in VLC played fine, including manual seek, but 1080p material first killed screen output then triggered the reboot. Fucking nuts. Too much window resizing also triggered it. But it gets weirder. After half a dozen restarts and auto-checkdisks, I currently haven't encountered the bug at all on my main partition.

Sounds like it could be something like hardware video decoding messing up the state of your GPU, which then crashes plasma.
You could try to switch your video player to software decoding, and see if that makes the issue go away. It's less efficient but a 3700x should be able to handle any video you throw at it.
- I remember omitting a hardware decoding line from mpv.conf. But I'm still getting the issue occasionally (even though playback in most cases now is fine).
  
  It does sound like the graphics side may be the culprit somehow. Not necessarily the hardware being broken, but the R9 is fairly old and perhaps support got broken somewhere along the way, and nobody ever noticed it?
  Are you using the radeon or amdgpu driver btw? There is a section on the Arch wiki that talks about into instability with the radeon driver specifically with the R9 390: https://wiki.archlinux.org/title/AMDGPU#R9_390_series_poor_performance_and/or_instability
  IIRC Plasma 6/QT6 does use vulkan heavily instead of OpenGL. Some additional things you could try:
  Disable kwin compositing
  Try to reproduce in another desktop environment
  Swap in a more recent GPU

6 comments