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Old 09-20-2021, 08:46 AM   #1
jskov
Junior Member
 
Join Date: Sep 2021
Posts: 1
Default Display layout changes on KVM switching

We experience an annoying problem when using a KVM to switch between
two computers (one Windows, one Linux) and two external monitors.

On Linux (Ubuntu 20.04, ThinkPad T490s), the display layout order
changes on the monitors on each KVM-switch.

So display preferences "2+3" changes to to "3+2", if that makes sense.

After each switch to Windows and back, we need to open the Displays
settings and reassign the display locations. It is maddening.

We are using Ubuntu 20.04 (Wayland) on ThinkPad T490s and a ThinkPad 40AF dock.


It is not clear to me, where in the "stack" this problem lies.
Is it in the driver? In Wayland? Gnome?

So this may not be the right forum to address. Apologies if not.

My (naive!) guess would be that there is no destinction between the
two monitors, as seen by the system. Maybe the monitor serial number
should be extracted from the EDID and used further up in the stack.

But if this was the explanation, then we should see stable displays on
half the KVM switches. And it does seem like it happens 90+% of the
time. So that is probably not it.


Any pointers would be appreciated.

Cheers,
Jesper Skov
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