How to fix Ubuntu brightness problem

How to play with Ubuntu brightness

Fix the fixed brightness

If you have faced the problem of fixed brightness of ubuntu then you are at the right place because after searching so much, i have finally found the solutions. Yeah you are right, solutions..! There are so many causes to this problem thats why i have listed the possible solutions.You can try each and every solution and do a reboot after applying solution.


  • Run this code in the terminal.xrandr --output LVDS1 --brightness 0.5 (It will not change the brightness but only the contrast. Also there is no need to reboot)
  • Editing Grub Configuration

    1. Run this commandsudo gedit /etc/default/grub. It will open the grub file.
    2. Change this code B_CMDLINE_LINUX_DEFAULT="quiet splash" to B_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
    3. OR (try the first one then second if first didn't work)
    4. Change this code B_CMDLINE_LINUX_DEFAULT="quiet splash" to B_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux"
    5. And if none of the above worked then try adding both the pieces.(believe me its this much varying)
    6. Then run update-grub. Now just reboot the system.
  • Now some more work. Go to the directory /sys/class/backlight.
    1. Check the interfaces there by running ls. There may be more than one like acpi_video0 OR intel_backlight. We'll perform the following steps for each interface and check the results.
    2. Go to your interface directory, for eg. intel_backlight.
    3. Run this command sudo echo 4 > brightness
      sudo echo 4 > max_brightness
      sudo echo 4 > actual_brightness
    4. Check if the brightness changes. If it does then you'll have to change it each time using this method only. And if it does not then repeat the procedure for other interfaces.
  • Newer kernel versions seem to have the problem so try to downgrade the kernel version to 3.12.

If it still not fixes the problem for you then get your laptop hardware checked or checking the graphics card properties. Although the second solution works for 80% of the people.


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