Playing with different resolutions and rates using xrandr solved the problem for me on a DELL XPS 15 with Ubuntu 18.04. If I go with a resolution of 1920x1080 and a rate of 60 Hz the TV shows a black screen. Changing to other modes and rates solves the problem. For example, typing in a terminal
xrandr --output DP-1-3 --mode 1360x768 --rate 60 made it work. If I go for a resolution of 1920x1080, I have output only for a rate of 25 Hz. I don't know why exactly this happens. Maybe it depends on the TV? -- 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/xorg-server/+bug/1771185/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs