I am running vino server on a laptop, and a vinagre on another. Both run Lubuntu 18.04. When the first laptop' Lubuntu 18.04 has screen locked, the vinagre on the other shows a black screen, and moving the cursor doesn't show login request. Is there some way to unlock server host's screen from VNC client side, without having to personally move to the VNC server host to unlock the screen? Thanks.
You should be able to connect to the other host via ssh as the user with the screen locked, then kill the screenlocking program, for instance if it's xscreensaver:
Caveat: I don't know what's the default screen saver for LXDE desktop or Lubuntu, it may be another program (
gnome-screensaver, etc). But that should work exactly the same any way.
Apparently LXDE screen-saver is
light-locker. Kill this one instead. If you want it to run again, open a terminal in the VNC session and run
Complement about X-Window:
When you're using SSH, you can access the screen you're connected from by using
ssh -X <host> or
ssh -Y <host>. Programs can perfectly run on a machine and display on another one. So if you run
light-locker through SSH on the remote machine, it will lock your local display and not the remote one (just as running
gnome-terminal or any other command will run it on the remote machine but display it locally).