Plasma 6.5.5 / Wayland / NVIDIA - After monitors power off and on, Desktop stutters every 8 seconds

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1

Apologies if this isn’t the correct place.

I have an NVIDIA RTX4090 on Fedora 43 on Plasma 6.5.5 (although I have seen in this OpenSUSE TW too on earlier versions of Plasma).

In “Power Management” I have “Turn off screen” set to 15 minutes. Once my monitors have powered off (but with the machine still live, not sleeping) and powered on again, my desktop will lag every 8 seconds.

If I look at NVIDIA SMI, I see it idles at P8, and then tries to go to P0, lags, and drops to P8 again.

If I run a game, it will stay at P0, but the wattage will drop from around 350W (depending on game) to around 200W at the same time that it lags.

Is there anything more I can do to diagnose this issue?

The only thing I’ve found that helps other than a reboot, is to turn VRR on and off again on the display device itself.

Thanks for any help!

2

Hi everyone,

Disclaimer: I’m relatively new to Linux and KDE. This post was generated with the help of opencode AI assistant after extensive diagnostic work. I hope this information helps the developers.

My Problem

I have 3 monitors connected to my NVIDIA RTX 3060:

  1. DP-1: 1920x1080@60 (rotated, scale 1.1)
  2. DP-3: 1920x1080@75 (rotated, scale 1.1)
  3. HDMI-A-1: 3840x2160@60 (scale 2.25)

The Issue:
When I disable any 1 monitor in System Settings → Display and Monitor (keeping 2 enabled), the entire desktop starts stuttering every 5 seconds:

  • Mouse cursor freezes
  • Display freezes
  • Input method (fcitx5) freezes
  • Everything becomes unresponsive for a brief moment

With all 3 monitors enabled, everything works perfectly.

System Information

  • OS: Arch Linux (rolling)
  • Kernel: 6.18.8-zen2-1-zen
  • KDE Plasma: 6.5.5
  • KWin: 6.5.5
  • Session: Wayland
  • GPU: NVIDIA GeForce RTX 3060
  • Driver: nvidia-open-dkms 590.48.01
  • ddcutil: 2.2.5

NVIDIA Configuration

Kernel Parameters:

GRUB_CMDLINE_LINUX_DEFAULT="loglevel=5 zswap.enabled=0 nvidia-drm.modeset=1"

Loaded NVIDIA Modules:

nvidia_drm
nvidia_uvm
nvidia_modeset
nvidia (main driver)

GPU Current State:

  • Driver Version: 590.48.01
  • Power Draw: ~21.67 W
  • Performance State: P8 (power saving)

Note: Using NVIDIA Open Kernel Module (nvidia-open-dkms) with modeset=1 enabled.

Diagnostic Steps Taken

With help from opencode, we performed extensive troubleshooting:

1. Checked Powerdevil

systemctl --user stop plasma-powerdevil.service

Result: Issue persists. Powerdevil is not the cause.

2. Checked KScreen Service

systemctl --user stop plasma-kscreen.service

Result: Issue persists. KScreen service is not the cause.

3. Checked ddcutil/libddcutil

  • All monitors show DDC/CI: disallowed
  • Environment variable POWERDEVIL_NO_DDCUTIL=1 set
  • Still getting infinite udev event loops in logs

4. Reset plasmashell Configuration

rm -f ~/.config/plasmashellrc
rm -f ~/.config/plasma-org.kde.plasma.desktop-appletsrc
rm -rf ~/.config/plasma-workspace
rm -rf ~/.local/share/plasma*
killall plasmashell
plasmashell --replace

Result: Issue persists even with fresh configuration.

5. Tested with kscreen-doctor

kscreen-doctor output.DP-1.disable
# Waited 30 seconds
kscreen-doctor output.DP-1.enable

Result: Issue occurs when using command-line tool as well, not just GUI.

6. Monitored System Logs

Monitored journalctl during the issue:

journalctl --user -f -t plasmashell -t kwin_wayland

Error Logs

Key Error (repeats every 5 seconds):

Feb 16 14:16:18 plasmashell[11202]: requesting unexisting screen available rect -1
Feb 16 14:39:04 plasmashell[11202]: requesting unexisting screen available rect -1
Feb 16 14:44:36 plasmashell[11202]: requesting unexisting screen available rect -1
Feb 16 14:59:51 plasmashell[11202]: requesting unexisting screen available rect -1
Feb 16 15:24:08 plasmashell[11202]: requesting unexisting screen available rect -1
Feb 16 15:26:49 plasmashell[11202]: requesting unexisting screen available rect -1
Feb 16 15:30:23 plasmashell[34416]: requesting unexisting screen geometry -1

KWin Main Thread Hanging:

Feb 16 13:43:38 kwin_wayland[979]: The main thread was hanging temporarily!
Feb 16 13:44:01 kwin_wayland[979]: The main thread was hanging temporarily!
Feb 16 13:44:42 kwin_wayland[979]: The main thread was hanging temporarily!
Feb 16 15:14:33 kwin_wayland[11109]: The main thread was hanging temporarily!
Feb 16 15:27:07 kwin_wayland[11109]: The main thread was hanging temporarily!
Feb 16 15:27:18 kwin_wayland[11109]: The main thread was hanging temporarily!

Other Errors:

Feb 16 15:30:23 plasmashell[34416]: error creating screencast "Could not find window id {caf62c4a-6795-4168-b565-95b9032a62bc}"

Happy to provide more logs or run additional tests if needed.

Thanks for any help!