I have a 4k LG monitor and it normally works just fine with Ubuntu. Today (3/15/2021) I installed updates, changed the audio settings from SPDIF output to the monitor, and rebooted. Now I have no resolution options other than 1024x768 and I can't figure out how to get them back. My monitor is no longer identified as a "LG 27 inch monitor" (it is 32", but linux always thinks it is 27").
Secure boot is set up correctly and I tried uninstalling the Nvidia 460 driver and installing the 450 version and that did not help.
xrandr output:
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1024 x 768, current 1024 x 768, maximum 1024 x 768
default connected primary 1024x768+0+0 0mm x 0mm
1024x768 76.00*
intel i7-6950x, Nvidia 1080 Ti
I finally got 4k resolution back after switching to the Nouveau display driver, but now Software & Updates shows this:
And it does not allow me to re-install a Nvidia driver. What could be going on here?
I've had the same problem today. Not sure what the answer is just yet, but this has happened to me a couple of times in the past and in the end it was a delay between a kernel patch being pushed and the corresponding Nvidia driver push. Normally I leave any updates for a week, but didn't notice kernel level ones in this update and applied them. For now, I have booted to the previous kernel and all works well.
Hopefully an updated Nvidia patch will arrive soon!.