I bought a laptop recently and installing Loki beta on it. Every special key works but backlight control, so I want to create a shortcut for it. Already try with xrandr but doesn't work. I found a solution with xbacklight but it doesn't send notification of the change.

So, my question is, what is the default command to increase and decrease backlight on elementary? I suppose is something with gala or similar, but I can't found myself

2 Answers 2


I think your keys are working but they aren't detected by the kernel driver, because I have the same problem, for fix that I added the parameter in /etc/default/grub

inline GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" add acpi_backlight=video so now it says GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=video"

then update the grub with sudo update-grub and reboot.

I hope this will fix your problem, that xbacklight or xrandr are legacy don't use that, let the kernel handle that.

  • Warning, doing this on Elementary OS 6 made my Sytem unable to boot due to kernel panic: Unable to mount root fs on unknown-block(0,0). Oddly enough, reinstalling made it work for me.
    – Checo R
    Aug 19, 2021 at 5:08
  • @ChecoR I think your problem was another one. Aug 19, 2021 at 16:16

Here is a cross post from another question I recently answered:

Cannot change brightness on lock screen

I make my own brightness hotkeys using xbacklight.

sudo apt-get install xbacklight

After xbacklight is installed:

Go into System Settings Keyboard Custom There is a little plus sign on the bottom right that says "add" when you hover over it.

Make two custom commands

xbacklight -inc 8
xbakclight -dec 8

Set the keys for these to

(ctrl + (brightness up key))

(ctrl + (brightness down key))

On my laptop I use (ctrl + f5) and (ctrl + f6) for my brightness keys.

What this is done it is possible that you can set your brightness to zero and get no video output. When that happens you will have to press the keys to increase your brightness to get your video back.

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