Running the latest version of RL and Mate on a Dell Inspiron 7570 laptop with a UHD display, i.e. 3840 x 2160 pixels. I would like to attach two external monitors and initially experimented with a Dell dock model 3100 and the latest version of the DisplayLink and evdi drivers. However, although the Mate display applet shows the correct resolution for the laptop display itself and for the external monitor which is running at 1920 x 1600 pixels, the resolution on the second, external display is more like 640 x 480 pixels.
While I initially thought this was due to a bug in the DisplayLink/evdi drivers, I see the same issue when I connect the monitor directly to the HDMI output on the laptop itself, ie. DisplayLink/evdi are presumably not involved although they are installed, nor is the dock of course.
Could this be an X11 bug (I am indeed running X11 and not Wayland)? How should I troubleshoot it?
Appreciate ideas!