Variant on the NotWakingUpAfterSuspend problem

I looked at many posts about this problem, but I could not find one that solved mine.

After I suspend or sleep my computer, it wakes up. I know because CtrlAltF1 shows me a console. But my desktop screen remains black and is unresponsive.

How can I wake up my desktop from a working console on the same computer?

What I've tried:

• Running set -display $DISPLAY dpms force on did not work, but it did give me unable to open display "". Same thing when I tried to set DISPLAY=:0 manually.
• sudo sysctrl unlock-session: nothing happened
• I can't reproduce this yet, but twice I've gone to a graphical message like your screen is locked. You will be forwarded to the unlock dialog (can't recall the exact wording). But the screen ends up going black again.
• startx on the F1 console started an empty desktop fine. So in principle, graphics capabilities are there.
• sudo system lightdm restart wakes that screen with a login dialog. Since it kills all running applications it's not really helping.
• Found some other bounty question with references to light-locker and xscreensaver. Never heard of either before, but followed what I read there. So I purged light-locker and installed xscreensaver xscreensaver-data xscreensaver-gl. After I logged in, I was asked to confirm to disable the lightlocker daemon which I did. But the problem remained. Maybe I need to do something else?.

Used Systems

• Xubuntu 16.04, latest update
• Desktop PCs, Atom CPU's /Intel on Board Graphics Cards
• the problem is with several motherboards
• Monitors: standard VGA noName TFTs

If you're having trouble with the Gnome screen-saver, replace it by the X Screensaver (which is what I did when I ran into a similar kind of issue:

• get rid of gnome-screensaver by:

  sudo apt-get purge gnome-screensaver
  sudo apt-get purge light-locker
  

Note: The light-locker purge should be automatic with the gnome-screensaver but as you were having trouble with that, added in as well.

• Install the X screensaver by:

  sudo apt-get install xscreensaver xscreensaver-data xscreensaver-gl
  sudo reboot
  

The reboot is in principle not necessary, but will ensure a "clean" system.

(It's just a workaround and not a real "solution" but it works for me and is definitely better then shutting down and restarting)