Seeing the "0mm x 0mm" part in the xrandr output makes me think that this may be a problem with obtaining the EDID information from the monitor. To check this, one would need Xorg.0.log with
Option "ModeDebug" "true"
in the "Device" section, and the output of `xrandr -verbose`.
Since the computer is no longer available for testing, I guess there is not much we can do unless someone else with a Lenovo ThinkCentre M55 comes around (?)
Seeing the "0mm x 0mm" part in the xrandr output makes me think that this may be a problem with obtaining the EDID information from the monitor. To check this, one would need Xorg.0.log with
Option "ModeDebug" "true"
in the "Device" section, and the output of `xrandr -verbose`.
Since the computer is no longer available for testing, I guess there is not much we can do unless someone else with a Lenovo ThinkCentre M55 comes around (?)