Light - when xbacklight doesn't work

Do you have any issues with controlling backlight on your laptop? Try light!

I’ve recently upgraded my laptop from F24 to F26, checked new Gnome features, killed it and switched to Qtile like I always do. Everything worked, so I moved to other things. Later that day I’ve put my laptop to my nightstand and went to bed. After a while of scrolling down the facebook page I decided to sleep, repeatedly pressed the function button to turn the backlight off, but nothing happened. WTF? Maybe I haven’t committed my key bindings with xbacklight, so they got lost during the reinstall? Nah, they are here. Well, maybe I can just restart the Qtile session. Nah, still doesn’t work … It took only a little while for me to … get off the bed, take my laptop and while cursing, sit back to the desk.

Long story short, I figured out, that xbacklight was the problem.

[jkadlcik@chromie ~]$ xbacklight
No outputs have backlight property

Never encounter this error before so I googled it. From results, you might learn that it is completely normal and you just need to symlink something with a cryptic name in /sys/devices and add some lines to /etc/X11/xorg.conf. Eh, I don’t want to do that? Besides, I don’t have a xorg.conf for like half a decade. Also, you can find an opened bug report from 2016, so waiting for a fix might take a while.

Then I finally found a blog post describing a solution that I liked most. It suggests using a handy little tool called light as a xbacklight alternative. It worked like a magic!

Installation

The only problem was, that light has not been packaged for Fedora yet. Since I was so happy about the tool, I decided to do my part and package it. Now you can easily install it from Copr by

dnf copr enable frostyx/light
dnf install light

There is also a pending package review so you might be able to install it directly from Fedora repositories soon.

Update: The package is already in Fedora repositories.

Usage

# Increasing brightness
xbacklight -inc 10
light -A 10

# Decreasing brightness
xbacklight -dec 10
light -U 10