Ubuntu – 18.04 Multiple monitor issues


I am using Ubuntu 18.04 LTS with gnome on a Thinkpad x250 connected to two external monitors through a docking station:

Monitor 1: Internal LCD, Disabled
Monitor 2: Dell 24"
Monitor 3: Eizo 17", Rotated

I have set them up accordingly in settings > devices > displays accordingly:

Settings Screenshot

But it seems to just act as one big display where the menubar or maximized windows extend across both screens, the 24" display is 'zoomed' (seems to render the combined resolution of both monitors) so moving the mouse to the sides pans the screen, and is vertically limited by the resolution of the smaller screen.

The smaller screen is 'anchored' to the top-right and does not pan.

I feel like this is some kind of mirroring issue, but I'm really confused as there is no mirroring option available?

The display behaves like so:

xrandr --current output: https://pastebin.com/7EhJrj5C

Best Answer

With the help of this solution, I realized it is just a matter of some basic math and xrandr commands which I will outline as simply as I can here:

Run xrandr to determine the names of your display outputs. In my case, I have:

  • eDP-1 (Internal)
  • DP-2-2 (External, Dell 1920x1080)
  • DP-2-1 (External, Eizo 1280x1024, rotated to the right)

Calculate the full size of your framebuffer --fb, in my case, I want to use only my external displays:


First clear/rest xrandr settings

xrandr -s 0

Then turn off the laptop display

xrandr --output eDP-1 --off

Then position the primary display to 0x0, set as --primary and set panning to its own resolution:

xrandr --output DP-2-1 --auto --scale 1x1 --pos 0x0 --primary --panning 1920x1080

Then position the second screen to the right at 1920x0, set the framebuffer and rotate it accordingly:

xrandr --output DP-2-2 --auto --scale 1x1 --pos 1920x0 --fb 2944x1280 --right-of DP-2-1 --rotate left

Popping these lines into a script I run after docking helps set everything up, and it resets back to the internal LCD when I remove it.

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