Thanks for the bug report. Most intermittent black screen flickers are caused by a loss of display signal integrity. It's especially common at high resolutions or refresh rates (I notice you're using 4K). That can usually be fixed by replacing the display cable and/or taking the dock out of the equation. So three things to try:
1. A new (higher grade) cable. 2. Another new cable that bypasses the dock (USB-C to DisplayPort or whatever you need). 3. Next time the problem happens, immediately run this command: journalctl -b0 > journal.txt and attach the resulting text file here, in case something relevant is being logged. ** Package changed: xorg (Ubuntu) => linux (Ubuntu) ** Changed in: linux (Ubuntu) Status: New => Incomplete ** Tags added: multimonitor -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/2076264 Title: Secondary external display intermittently goes black To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2076264/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp