Setting up Dual Monitors on Ubuntu 18.04

post by generativist on Sep 9, 2018

I’m having trouble setting up dual monitors on Ubuntu 18.04 for my Lambda Quad.

Physical configuration:

• One monitor in gpu0 plugged into the HDMI port
• One monitor in gpu1 plugged into the HDMI port

Issues:

• On the Ubuntu login screen, both monitors are active. I can move my mouse to the non-primary one, and the cursor is visible and identical to when it is on the primary monitor.
• When I login, the cursor on the secondary monitor reverts to a ‘X’ cursor and I cannot do anything but move it on that screen.

I’ve tried fiddling with settings in NVidia X Server configs. (Actually, I had to overwrite my xorg.conf to get anything on the second monitor at all.) But, I’ve no spent four hours on this with no success.

Has anyone got this working?

post by russellizadi on Oct 10, 2018

I have exactly the same issue.

I tried different xorg configuration but none are working. Also, when I enable Xinerama, neither of monitors work.

post by sabalaba on Oct 11, 2018

You should try to plug both monitors into gpu0. I think that the problem is trying to use multiple GPUs to drive multiple monitors. Depending on your GPU model (PNY/ASUS/GigaByte 1080 Ti / Titan V / 2080 Ti) you will have different numbers of HDMI / DisplayPort ports. If you have two HDMI ports per GPU, try plugging both HDMI cables into GPU0.

If you do not, you will need to purchase an HDMI to DisplayPort cable or adapter like this:

Unfortunately despite it being the 21st century, Xorg, nvidia-settings, xinerama, xrandr, and multi-monitor support in general on Linux is finicky at best.