After upgrading to 18.04 Ubuntu monitor is unknown

Question

Have been running Ubuntu Mate 17.10 and just upgraded to 18.04 LTS. But after upgrading my monitor settings are all wrong and can't set the proper resolution. How can I resolve this?

Solution

I had this issue and first switched to nouveau driver which fixed my laptop's display, but did not allow me to connect a second monitor. I fixed that issue running:

sudo ubuntu-drivers devices

which showed that the nvidia driver was recommended. driver : nvidia-driver-390 - distro non-free recommended driver : xserver-xorg-video-nouveau - distro free builtin

So I then ran

sudo ubuntu-drivers autoinstall

which installed and used the nvidia driver. After rebooting sudo shutdown -r now it worked!

This is the post I followed to get those instructions.

Comments

[HelloGoodbye]

Do you have an NVIDIA GPU? In that case, you might try reinstalling your graphics card driver and see if that helps (that worked for me when my monitor was suddenly classifier as "Unknown," although I'm not sure what caused it to loose its recognition).

[Cliff Armstrong]

You should also make sure you are not using a VGA adapter for your monitor. Use either DVI, HDMI, or Display Port. No VGA on either end.

[HelloGoodbye]

I'm getting sudo: ubuntu-drivers: command not found when I try this, and I don't find any package with that exact name. I find ubuntu-drivers-common, though; is that equivalent?

[derricki]

I checked and I think that is the package where my executable came from.