15.4 LXQT - xScreensaver to full black or change the screensaver?

running 15.4, LXQT

Xscreensaver does not fully blackout the monitors. They look black, but at night there is a gray glow. Is there a setting on that or another screen saver that could be changed? I would prefer the monitors to go black for the health of the monitor as well as eliminating a light source at night. I know that the Cinnamon screen saver does go to full black. I have installed that within LXQT, but it will not run.

I have found this on line, but no success yet.
Replace xscreensaver locker with a better tool (sddm, gdm3) on Lubuntu (LXQt) - Ask Ubuntu

Navigate to Menu » Preferences » LXQt Settings » Session Settings » Autostart
Uncheck the check box next to Xscreensaver
Click the Add button
In the Name field add something like "xautolock xtrlock"
In the Command field add xautolock -locker "xtrlock -b"
Click OK
Click Close
Log out and back out again

For Cinnamon Screensaver (which I do like, but am open to others) here is a link to the man pages.

Trying to test it via command prompt errors as:

:~> sudo cinnamon-screensaver-command -a
[sudo] password for root: 
(cinnamon-screensaver-command:27748): GLib-GIO-ERROR **: 10:52:29.957: Settings schema 'org.cinnamon.keyboard' is not installed
Trace/breakpoint trap

dad@localhost:~> cinnamon-screensaver-command -a
Invalid MIT-MAGIC-COOKIE-1 keyInvalid MIT-MAGIC-COOKIE-1 key
(cinnamon-screensaver-command:27754): GLib-GIO-ERROR **: 10:52:34.923: Settings schema 'org.cinnamon.keyboard' is not installed
Trace/breakpoint trap (core dumped)

The same error messages came up with cinnamon-screensaver --no-daemon

Thank you for any help.

1 Like

For saving energy and going black you don’t use screensavers. Screensavers are ancient tools for old monitors and still waste a lot of energy. Nowadays you should switch of monitors automaticaly if there is no keypress/mouse movement for a defined time.

You should have a look in the power management settings of Lxqt.

1 Like

Thank you. I was not aware of that. I see in the settings under Idle, When idle on AC: Turn off monitor(s). That looks like it will do the trick.

What is the difference between “lock screen” and “turn off monitors”? Beyond the obvious. The LXQT manual doesn’t elaborate.

Does it require the login password to turn them back on and “unlock” the system?
Is the system actually locked, or are the monitors just off?

Lock screen: locks your session so that you need to enter your user password
Turn off: Turns off (electrically) your monitor.

That means you should lock your screen if you don’t want anybody else have access to your session, and after a defined time the screen will turn of automatically.
As example under Plasma you can easily lock your screen with WIN+L key combo…should also work with Lxqt.

Will it allow viewing a movie, ie, no mouse or keyboard activity, but stays open for video?

I’m not using Lxqt, so you can test yourself. Set the timeout when the monitor should turn off to 1 minute. Test without doing anything and afterwards with playing a video.

Under Plasma playing a video with VLC prevents the monitor going off…so normaly also Lxqt should detect playing a video and prevent powersaving. But VLC also has a setting to turn off screensaver whilst playing…

Ran the test. It did not lock the screens, but stated that it needed xscreensaver.

Failed to run  "xdg-screensaver lock". Ensure you have a locker/screensaver compatible with xdg-screensaver installed and running.

This error is a Lxqt bug…

But after installation of xscreensaver and restart of the machine, you should be able to lock your screen.

And then you can test if your screen switches of after the defined time that you set in power management settings.

1 Like

It is working now after reselecting the xscreensaver in the LXQT Session Settings/Autostart.
The blank screen does not require a password to reopen
If however I select lock screen, that takes effect, and the blank screen takes over based on the idle selection (15 mins). So though it is a bit clunky it is working.

It does not however stay open without moving the mouse throughout a movie.

So my previous question is still on the table.
Does anyone know how to get the Cinnamon Screensaver to work in LXQT?

This may have been what you meant early and I didn’t catch it.

The solution is to stack the Xscreensaver (just for fun) set to 10 minutes, and the LXQT Power Settings to turn off the monitors at 15 minutes. The goal was to have the option of a secure screen lock that will turn off the monitors.

The result is after 10 minutes the screen animation starts, then at 15 minutes the monitors turn off.

The only question now is how to keep it open while streaming a video.

thanks all.

Yep, this was what i meant. First lock the screen (via screensaver with pw prompt) and then let it switch off.

How to keep the monitor “alive” whilst streaming:
It is possible that it depends on the used mediaplayer. As i mentioned above, VLC has a setting to disable screensaver whilst playing. This setting also prevents the switchoff of screen.


For the video VLC is my choice also. The challenge is with the streaming apps.

the answer may be Caffeine. Trying it now.

looks like Caffeine should be the answer for streaming. It is supposed to run in the system tray. However it is not, and i cannot start it via terminal, nor is it in the menu after installing it from the openSuse software search. I will open a new question for that issue.