Update: I thought it might be a permission problem, so I tried configuring my monitors manually using "sudo xrandr...". Same result - error dialog and fallback to mirroring.
I attach a more accurate photo of the error dialog that pops up at every failure - sometimes for more than one monitor, with different identifiers of "CRTCXXX".
Update: I thought it might be a permission problem, so I tried configuring my monitors manually using "sudo xrandr...". Same result - error dialog and fallback to mirroring.
I attach a more accurate photo of the error dialog that pops up at every failure - sometimes for more than one monitor, with different identifiers of "CRTCXXX".