Ubuntu – Disable automatic screen dimming

brightnesspower-managementscreen

I currently have three computers running Ubuntu. With two of them, If I don't touch the mouse or keyboard… nothing happens. However, with the third, the screen gets dimmer after about 60 seconds of inactivity. I can't seem to figure out how to prevent this.

I've tried using the control center (gnome-control-center –overview), entering the "Brightness and Lock" screen, and unchecking the "Dim screen to save power" checkbox, but that doesn't actually seem to have any effect on the issue.

I'm running 32-bit Ubuntu 13.04, with the Cinnamon desktop. I also used to have KDE-Plasma, although I decided to get rid of it. Any Ideas?

Best Answer

I seem to have found the cause of the problem, as well as the solution; apparently,there was some strange power management package installed.

I noticed a few weeks ago that the hard drive was powering down after three or four seconds (literally) of inactivity. So, after attempting to remedy the hard drive issue using the software from THIS page, I get a message telling me that tlp can't start because of a package called laptop-mode-tools, as well as a recommendation to remove it.

So, I powered up another Ubuntu laptop, which hasn't given me any real problems, and checked to see if it had that same package (using sudo apt-get purge laptop-mode-tools -s), and found that said package didn't exist, which made me assume it probably isn't particularly necessary. After removing both packages (that is, tlp and laptop-mode-tools), and rebooting the system, the both hard drive spin-down, and the dimming screen issues were solved.

Caffeine

You could try using caffeine. When you activate caffeine the screen wont fall a sleep or get dimmed, you can set it up in different ways.

You can find more info here, or on launchpad.
And install the program by typing sudo apt-get install caffeine

Ubuntu – How to make the screen brightness not change when I plug the laptop in

I tested a solution that works fine for me. One solution is to add a script file in /etc/pm/power.d/

Just creates a file

sudo vi /etc/pm/power.d/run_after_pwrmanagmt.sh

Then writes this code into this file :

case "${1}" in
    true) #battery_mode
        xinput set-int-prop 12 277 8 2 3 0 0 1 3 2
        echo 4000 > /sys/class/backlight/intel_backlight/brightness
;;
    false) #ac_mode
        xinput set-int-prop 12 277 8 2 3 0 0 1 3 2
        echo 4000 > /sys/class/backlight/intel_backlight/brightness
esac

Now, you need to give execution rights to this file by typing

sudo chmod +x /etc/pm/power.d/run_after_pwrmanagmt.sh

Now it should work fine, just test to plug/unplug your computer. Note that you can do similar things after a suspend (/etc/pm/sleep.d/run_after_sleep.sh), that's how I found out this solution... You will find information on the web...

Note that xinput is just a command for my trackpad to set the middle button working... You should skip the two lines xinput if not needed (or adapt ). For the value 4000, it may be diffrent for each screen, you should first see what is your max value with the command cat /sys/class/backlight/intel_backlight/max_brightness

Hope this helps, and that the moderator will not delete this post since this is an answer and not a question. Thanks

Best Answer

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Ubuntu – How to disable screen dimming after inactivity when this is already disabled at system settings

Caffeine

Ubuntu – How to make the screen brightness not change when I plug the laptop in

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