light-locker doesn't power down both monitors [xubuntu 18.04]

[MortenGuldager]

I upgraded my dual monitor xubuntu desktop machine from 16.04 to 18.04.

Now light-locker blanks both monitors as it should, but it only powers one of them down.

Both xubuntu's native XFCE Power Manager and xset dpms force off are able to control power down on both monitors, just not light-locker.

I need some guidance on how to investigate and solve this.

Light-locker power management appears to be an old classic; most answers goes along the lines "uninstall light-locker and use xscreensaver". I can do that, but it seems backward.

[Autodave]

Hopefully someone with a better idea will jump in here, but upgrading from one release to another rarely works without issues. I always backup everything to an external drive and do clean installs.

[1fallen]

I have also seen problems with lightlocker/xscreensaver conflicts in the past with Lubuntu/Xubuntu.

I just prevented lightlocker from automatically starting by executing


sudo mv /etc/xdg/autostart/light-locker.desktop /etc/xdg/autostart/light-locker.desktop.bak

This is totally reversible should it cause any problems.
NOTE: there is probably a more elegant way.

[MortenGuldager]

I have also seen problems with lightlocker/xscreensaver conflicts in the past with Lubuntu/Xubuntu.

Ah yes, we are not alone with our light-locker issues



I just prevented lightlocker from automatically starting by executing

sudo mv /etc/xdg/autostart/light-locker.desktop /etc/xdg/autostart/light-locker.desktop.bak

This is totally reversible should it cause any problems.
NOTE: there is probably a more elegant way.

And I could do the same, simply dumping light-locker altogether and go with something else, say xscreensaver. But I kinda like light-lockers clean and simple system, if I just could get it working properly.