Ubuntu – How to prevent Ubuntu from changing the laptop screen brightness level


I have installed Ubuntu 12.04 LTS on my dell inspiron 1464. Everything is working fine. Except my LED brightness.

Every time I adjust it to my suitable level. But after reboot it goes on high as it was before. This is quite irritating specially at night.

I do not face this problem in previous version. How can I lock my brightness to my preference?

Best Answer

  • I faced the same problem on my Dell XPS. Currently there is no other way to save it according to brightness key.

    • First try executing

      sudo su -c 'echo 5 > /sys/class/backlight/acpi_video0/brightness'

    If it succed,try with different value for 5 and choose your preference level.

    • Now edit /etc/rc.local file to execute this command at boot up.

      gksu gedit /etc/rc.local
    • Just before exit in the file, add the following line,

      echo 5 > /sys/class/backlight/acpi_video0/brightness

    You can change value 5 to anything.