Change Display priority (KDE/Lightdm)

I have a slightly unusual configuration in that I have 4 different systems (2 Windows, 1 EOS, and 1 MacOS) that all connect into 3 separate screens. Each screen has only one input… which is a HDMI splitter of 4 in/1 out. During the day I’ll cycle between each of the four for different tasks by changing the HDMI splitter number.

So for my EOS system, the only issue is that when I switch to it, the screens are not arranged in the order that they are physically (ie screen on the far right, thinks its on the far left). So I’ve put a script on my desktop that re-arranges them as they are physically using xrandr. The problem is though, that even though xrandr tries to configure the screen in the centre as the primary, the KDE taskbar remains on one of the screens on the left or right, and I need to right click on a space on the desktop, select “Configure Display Settings”, click “Change Screen Priorities” and move the screen in the middle to the highest priority to get the taskbar to be there.

I realize in the greater scheme of things this is a relatively trivial annoyance, but is there a way to script this so I don’t manually have to do it?

Xrandr command used is

xrandr --output HDMI-2-5 --primary --mode 1920x1080 --pos 1920x0 --rotate normal --output DVI-D-1 --mode 1920x1080 --pos 3840x0 --rotate normal --output HDMI-4 --mode 1920x1080 --pos 0x0 --rotate normal

So I want HDMI-2-5 to be the highest priority if possible

If you are confident that this command will always work (monitor output names randomly change), then create an executable script with this command, and set it as display-setup-script= value in the [Seats.*] section of /etc/lightdm/lightdm.conf.

Test it well, and be prepared for a black screen, just in case… (switch to TTY and rename the file).

Plasma has done a lot of progress with multi-monitors, so maybe you try the available options in System Settings/Display, before using the above (if lightdm itself is not important). You might also want to ask at the KDE forum.

The monitor names haven’t changed so far that I’ve seen, but I haven’t been using EOS for all that long to predict if they will in the future with updates etc. So I’ll try this out and see how it works. Thank you.

I’m not wedded to Lightdm, its what it defaulted to on installation, if any of the alternatives don’t have this issue, I’d be more than willing to change. Previous to this I was using Manjaro KDE/SDDM and it didn’t have this option or problem, so maybe its worth trying SDDM again.

Frankly, I have no idea what this issue is. I just gave a quick advice :person_shrugging: .
Without investigation, logs, etc., your case (with a kvm switch) cannot be really understood remotely. :wink:
Each vendor, developer and user mean different things with terms like screen, monitor, display, primary, etc.

DMs usually provide an Xsetup script option, so the end users adjust the initial display (Login screen) to their specific setup and preferences. SDDM does this as well.

Are you not able to set this up on EOS with /etc/X11/xorg.conf.d/10-monitor.conf file?