Ubuntu – Screen does not turn off when inactive


Recently I have noticed that the brightness and lock settings to turn off the screen after a period of inactivity are being ignored.

I have my settings at 1 minute and to lock the screen when the screen turns off but my computer never seems to turn the screen off.

I have seen similar questions where people are noting an issue where the screens turn back on and the lock screen is showing but I am not getting the computer to lock at all.

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Best Answer

I can offer a workaround to this

Never mind the settings in the GUI, you can lock your screen and send your screens into standby via the command line

To lock your screen you could use

gnome-screensaver-command -l

or (if don't use gnome3)

xdg-screensaver lock

and to turn off your monitors (standby) you could use

xset dpms force off

Now, since you don't want to do this manually, but after a couple of minutes idle time, we need to find out how long you have been idle. This can be done with xprintidle

sudo apt-get install xprintidle

xprintidle will return miliseconds of (xserver) idletime

Now, lets combine this into a script(*). Use your favorite editor to copy/paste the following, modifying the IDLE_TIME to your liking

nano /home/yourusername/idle_stby_lock_screen.sh

# Wanted trigger timeout in milliseconds.
IDLE_TIME=$((5*60*1000))  # replace the '5' with how many minutes you'd like

# Sequence to execute when timeout triggers.
trigger_cmd() {
    echo "Triggered action $(date)"


while sleep $(((sleep_time+999)/1000)); do
    if [ $idle -ge $IDLE_TIME ]; then
        if ! $triggered; then
            gnome-screensaver-command -l
            export DISPLAY=:0; xset dpms force off
        # Give 150 ms buffer to avoid frantic loops shortly before triggers.

Then make it executable with

chmod +x /home/yourusername/idle_stby_lock_screen.sh

You can test it out on the commandline


if you are content with it, you can add it to the startup of your Ubuntu, like described in these answers here or with the "Startup" app in Ubuntu - just make sure to use the absolute path to your script.