Remap backlight/brightness to other keys on XFCE

Question

I have a laptop with Manjaro XFCE and I damaged my F2 and F3 keys, which operate the brightness of the display (up and down respectively) while holding the Fn key.

The xfce-power-manager works fine, and I can use the slider on the bottom bar, but I would like to know if I can remap brightness to other keys. I haven't been able to find a solution for now.

I tried instaling light package, as I saw in another reply, and using:

light -U 20

decreases the brightness as expected, but it has to be done as root, so my idea to remap that command to another key combination, doesn't work, because it doesn't have privileges.

Any idea? Thanks!

Answer 1

Finally I got to a solution. Here is what I did (better ways would be welcome!)

1. Instead of xorg-xbacklight package as showed in the Arch Wiki as default option (because I got the error "no outputs have backlight property" that the wiki talks about, and using the .conf parameters showed in the wiki didn't solve it for me) I installed: acpilight package. It runs the same way as xorg-xbacklight:

   • xbacklight -inc 10 to increase, and
   • xbacklight -dec 10 to decrease. As suggested by @ArtemS.Tashkinov here in the comments.

2. To control xbacklight and chenge backlight level, you need sudo privileges, so I needed to edit sudoers to make my user able to run the xbacklight command without asking for the password (but, for security reasons, of course, only that, and not any command):

   1. sudo visudo (vim like editor) or su and then visudo (with your default editor, in case your are used to nano)
   2. Add the following (changing username for your user):

      username ALL=(ALL) NOPASSWD: /usr/bin/xbacklight
      

3. To avoid the possible error (I had it) /usr/bin/xbacklight: [Errno 13] Permission denied: '/sys/class/backlight/intel_backlight/brightness'; I added my user to the video group, which is the default in 90-backlight.rules (as I saw here) (change username for your user name):

   sudo usermod –a –G video username
   

4. Create two scripts called bright-up.sh and bright-down.sh (or whatever you want), with this content:

   #! /bin/bash
   
   xbacklight -inc 10
   

   • Change -inc for -dec in the bright-down.sh
   • Change 10 for the value you want, like 5 or 20, depending on how much you want the brightness to change.

5. Place those scripts in a directory like /home/user/.bin/ or wherever you want and give them execute permissions:

   chmod +x /home/user/.bin/brigh-up.sh /home/user/.bin/bright-down.sh
   

6. Now create keyboard shortcuts pointing to those scripts according to your desktop environment/window manager. In XFCE in keyboard > keyboard shortcuts.