KWin Wayland DRM atomic commit failure causing crash loop (open GPU kernel modules)

NVIDIA Open GPU Kernel Modules Version

580.119.02

Please confirm this issue does not happen with the proprietary driver (of the same version). This issue tracker is only for bugs specific to the open kernel driver.

• I confirm that this does not happen with the proprietary driver package.

Operating System and Version

NixOS 25.11 (Xantusia)

Kernel Release

Linux nixos 6.18.1-zen1

Please confirm you are running a stable release kernel (e.g. not a -rc). We do not accept bug reports for unreleased kernels.

• I am running on a stable kernel release.

Hardware: GPU

NVIDIA GeForce RTX 3060 Ti

Describe the bug

KWin fails to reliably apply DRM atomic modesetting when running a Plasma Wayland session on NVIDIA GPUs using the open GPU kernel modules.

During Wayland startup and output configuration, KWin reports DRM atomic modeset and commit failures with “Permission denied”. In some cases this results in a crash loop during login via SDDM; in other cases the session remains active but output configuration fails, indicating an intermittent DRM atomic failure in the NVIDIA driver.

The GPU is correctly assigned as DRM master, and the issue does not occur on AMD or Intel hardware with the same software stack.

To Reproduce

Preconditions:

• NVIDIA GPU
• NVIDIA proprietary userspace with open GPU kernel modules (nvidia-open)
• DRM modesetting enabled
• KDE Plasma 6.x, KWin 6.x, SDDM
• Wayland session

Steps:

• Boot the system normally
• At SDDM, select “Plasma (Wayland)”
• Log in
• During startup or display configuration, KWin reports DRM atomic failures

Observed journal messages include:

• “Atomic modeset test failed! Permission denied”
• “atomic commit failed: Permission denied”
• “Applying output configuration failed”

Bug Incidence

Sometimes

nvidia-bug-report.log.gz

nvidia-bug-report.log.gz

More Info

drm_NVIDIA.log
journal_kwin_wayland.log
kwin_wayland.log
nvidia-smi.txt
seat0.txt
uname.txt

Start with the attached drm_NVIDIA.log, journal_kwin_wayland.log, kwin_wayland.log, nvidia-bug-report.log.gz, and the reported kernel and driver versions. Reproduce the Plasma Wayland login and output-configuration sequence on the RTX 3060 Ti, then compare the DRM atomic failure messages with the observed crash loop. Done means the failure is explained and the session no longer crashes or loses output configuration under the stated setup.