I also have this problem, which has been bugging me also in the pre- alpha releases of 18.04. It happens occasionally to me on a Thinkpad E580, and was expecting hardware-like resume problems, or issues with light-locker.
I noticed that connecting an external display worked for the external display, so the desktop was running properly. Trying to revive my laptop display using xrandr gave me an error: "Configure CRTC 0 failed". I found a solution posted here that works for me: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=785622 Which is: xfsettingsd --replace ** Bug watch added: Debian Bug tracker #785622 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=785622 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1431149 Title: XFCE 4.12 Black screen after wakeup from suspending by closing the laptop lid To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xubuntu-default-settings/+bug/1431149/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
