I'd point my finger a the amdgpu driver in that case. Unplugging the monitor in question did the trick (allowed system to blank properly). The cable is definitely good & the connection ports on both ends should be fine. This particular system is dual booted into Windows 10 where this is a non-issue.
The keyboard has always been wonky (frequently it doesn't get initialized and has to be unplugged and plugged in again). I left it plugged in to run the test & the system was not adversely affected. The same amdgpu is plugged into two monitors: [1] monitor with issue (straight HDMI <> HDMI) FreeSync compatible [2] monitor that works fine (DP on gpu converted to HDMI) non-Free-Sync -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1835863 Title: Screens do not stay off when blanking To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-amdgpu/+bug/1835863/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs