Found a workaround: xrandr --addmode HDMI-1-2 1920x1080 xrandr --output HDMI-1-2 --mode 1920x1080
This sequence of commands enables clone display. However, I still don't see anywhere in Displays/Monitors the secondary display. Here is the xrandr output (while projector is on): HDMI-1-1 disconnected 1920x1080+0+0 (normal left inverted right x axis y axis) 0mm x 0mm 1920x1080 60.02* -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1771185 Title: Secondary monitor not connecting in 18.04 LTS To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libxrandr/+bug/1771185/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs