How to persist display settings?

Question

I my display configuration to remain like this:

Yet after each reboot, it resets to:

How to have it persistent?

My xrandr output:

Screen 0: minimum 8 x 8, current 4920 x 1920, maximum 32767 x 32767
eDP1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 309mm x 174mm
   1920x1080      60.0*+   59.9     48.0  
   1680x1050      60.0     59.9  
   1600x1024      60.2  
   1400x1050      60.0  
   1600x900       60.0  
   1280x1024      60.0  
   1440x900       59.9  
   1280x960       60.0  
   1368x768       60.0  
   1360x768       59.8     60.0  
   1152x864       60.0  
   1280x720       60.0  
   1024x768       60.0  
   1024x576       60.0  
   960x540        60.0  
   800x600        60.3     56.2  
   864x486        60.0  
   640x480        59.9  
   720x405        60.0  
   640x360        60.0  
DP1 disconnected (normal left inverted right x axis y axis)
DP1-1 disconnected (normal left inverted right x axis y axis)
DP1-2 disconnected (normal left inverted right x axis y axis)
DP1-3 connected primary 1080x1920+1920+0 left (normal left inverted right x axis y axis) 477mm x 268mm
   1920x1080      60.0*+
   1680x1050      60.0  
   1600x900       60.0  
   1280x1024      75.0     60.0  
   1280x800       59.8  
   1152x864       75.0  
   1280x720       60.0  
   1024x768       75.1     60.0  
   832x624        74.6  
   800x600        75.0     60.3  
   640x480        75.0     60.0  
   720x400        70.1  
HDMI1 connected 1920x1080+3000+0 (normal left inverted right x axis y axis) 477mm x 268mm
   1920x1080      60.0*+
   1680x1050      59.9  
   1600x900       60.0  
   1280x1024      75.0     60.0  
   1280x800       59.9  
   1152x864       75.0  
   1280x720       60.0  
   1024x768       75.1     60.0  
   832x624        74.6  
   800x600        75.0     60.3  
   640x480        75.0     60.0  
   720x400        70.1  
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

Answer 1

If I made no typo, the command:

xrandr --output eDP1 --pos 0x0 --output DP1-3 --pos 1920x0 --rotate left --output HDMI1 --pos 3000x0

should set up the screens like in the image (please try first). To make it stick on next login, add to startup applications:

/bin/bash -c "sleep 15 && xrandr --output eDP1 --pos 0x0 --output DP1-3 --pos 1920x0 --rotate left --output HDMI1 --pos 3000x0"

Add it to Startup Applications

Choose Dash > Startup Applications > Add. Add the (second) command above. The sleep 15 is to make sure the desktop is fully loaded, else the setup will likely break or be overruled by local procedures.

Explanation

Using xrandr, you can get information on the current screen setup. In the output you posted, three screens appear to be connected (which we expected :) ):

eDP1 connected 1920x1080+0+0
DP1-3 connected primary 1080x1920+1920+0
HDMI1 connected 1920x1080+3000+0

The section:

1920x1080+0+0

gives us information on the screen's resolution (1920x1080) and its position in the whole picture; the coordinates from the top left corner of the combined screens' layout (+0+0, which is x/y).

Subsequently, we can set the position of a screen, using the command:

xrandr --output eDP1 --pos 0x0

and its rotation:

xrandr --output eDP1 --rotate left

In case we need to set up a layout with multiple sreens, we need to run the sequence of commands from the left to the right screen.