SDDM doesn't start and Neon doesn't use the GPU driver

It started with out of the blue, none of my Flatpaks working.

bwrap: Creating new namespace failed: Permission denied
error: Failed to sync with dbus proxy

I read running sysctl kernel.unprivileged_userns_clone=1 might be worth trying, but it somehow resulted in a low-resolution super slow, laggy boot.
I checked, and the graphics processor was lvmpipe, so I removed nvidia packages, then had a high-resolution boot where I got to SDDM and could log in but extremely laggy. I installed the latest driver with ubuntu-drivers install.

The boot sequence stops after reaching, even though systemctl get-default returns so I don’t get to SDDM

I can login in the terminal and startx, but that returns in a very low-resolution boot with only one monitor (of 2) working. The graphics processor is still lvmpipe.

NVIDIA-SMI has failed because it couldn't communicate with the NVIDIA driver. Make sure that the latest NVIDIA driver is installed and running.

Operating System: KDE neon 5.27
KDE Plasma Version: 5.27.6
KDE Frameworks Version: 5.107.0
Qt Version: 5.15.10
Kernel Version: 5.19.0-1010-nvidia-lowlatency (64-bit)
Graphics Platform: X11
Processors: 8 × Intel® Core™ i7-3770 CPU @ 3.40GHz
Memory: 31.3 GiB of RAM
Graphics Processor: llvmpipe

I have been seeing a number of instances of people reporting this lowlatency kernel causing issues in *buntu, breaking nvidia drivers for it.
It also seems to be installing these lowlatency/oem kernels on some systems as well, You might want to try booting to a previous normal kernel, instead of the low-latency one.

This doesn’t seem to be a neon issue, specifically.


Thanks for the tip, but the same happens with a different kernel

Here’s the output of journalctl --catalog --boot

and the nvidia bugreport:

There was an apt error while installing the NVIDIA drivers, reinstalling them thankfully solved the problem.
sudo apt install nvidia-driver-535
*not sure what caused the problems in the first place, though

Thanks, there were other problems, but the driver finally loaded with a different kernel