I have upgraded my Kubuntu system (desktop workstation with Nvidia GPU) multiple times, and I am using the nvidia binary driver. Recently, after upgrading to 18.04 (bionic), I was facing a black screen with a mouse cursor after booting up. Apparently, I was using sddm, and debugging this I found
GREETER: Could not initialize GLX
I also found the following, more detailed message using
journalctl -e -t sddm-greeter:
Failed to create OpenGL context for format QSurfaceFormat(version 2.0, options QFlags<QSurfaceFormat::FormatOption>(), depthBufferSize 24, redBufferSize -1, greenBufferSize -1, blueBufferSize -1, alphaBufferSize -1, stencilBufferSize 8, samples -1, swapBehavior QSurfaceFormat::SwapBehavior(DoubleBuffer), swapInterval 1, profile QSurfaceFormat::OpenGLContextProfile(NoProfile))
I tried uninstalling and reinstalling many things (for instance,
nvidia-driver-390 and everything related to nvidia), and eventually switched from sddm to lightdm. Now, I could log in, but KDE would also not properly start; the message is
Plasma is unable to start as it could not correctly use OpenGL 2. Please check that your graphics drivers are set up correctly.
When I manually start plasmashell and krunner, I start getting a usable desktop, but a very unstable KDE session with a frequent flashing & popup
Desktop effects were restarted due to a graphics reset
Question: What may cause these messages, and how should I continue debugging this?
Here are some facts that may be relevant, starting with the more suspicious ones:
- Probably unrelated: For some reason, I also had severe problems getting nvidia-docker to work again after the upgrade, but could fix that by editing
/etc/nvidia-container-runtime/config.tomlto adapt to my
- lightdm does not start automatically on boot, but I can do
sudo service lightdm restartin order to get a login screen.
- I have heard that Ubuntu changed from running X on vt7 to vt1, but on my system it is still running on vt7. No text-mode login is running on vt1, though.
- I also have problems with DBUS; for instance, muon cannot contact an authentication agent via DBUS (dbus daemons seem to be running, though, so maybe the problem are again KDE services).
The following things I checked looked perfectly fine to me:
glxgearsand some other GL-using programs seem to work fine.
glxinfoseems to confirm that I am using the nvidia driver (now, version 410 from the graphics-drivers PPA) successfully, and that my graphics card is recognized.
- A non-KDE app I tested (MeVisLab) is able to make advanced use of OpenGL and reports OpenGL version 4.6.0 without problems.
nvidia-settingsalso looks normal.
/var/log/Xorg.0.loglooks normal to me.
- I can run demanding programs using CUDA and my GPU, both through nvidia-docker and without.
- I am not using prime;
/sbin/prime-offload, which seems to write "Sorry but your hardware configuration is not supported" into
/var/log/prime-supported.logcontains "No offloading required. Abort"
I think the following questions may be referring to the same problem I have, but they're all unresolved and the descriptions did not match perfectly (notebook vs. desktop, for instance). I preferred to start from scratch and to decide after (hopefully) resolving the problem whether they're duplicates: