Have an external monitor supports DDC/CI protocol? There’s a free and open-source graphical tool to control the brightness for your display.
Display Data Channel (DDC) / Command Interface (CI) is a type of communication between the computer and the monitor.
Most monitors today support DDC/CI, but not many people have heard of it, since most manufacturers do not develop proprietary software for the feature.
If you have computer monitors purchased in the past few years, DDC/CI should be supported. After enabled the feature via your monitor’s physical settings button, installing
ddcutiland its graphical UI will allow you to control the display brightness in Linux desktop.
Step 1: Install ddcutil & ddcui
1. First, open terminal by either searching from system app launcher or pressing Ctrl+Alt+T on keyboard. When it opens, run command to add the developer’s PPA:
sudo add-apt-repository ppa:rockowitz/ddcutil
Type user password (no asterisk feedback) when it asks and hit Enter to continue.
Ubuntu 22.10 & Ubuntu 23.04 can SKIP this step, since the packages are available in system repositories.
2. Linux Mint user need to manually refresh system package cache after adding PPA, though it’s done automatically in Ubuntu since 20.04. To do so, run command:
sudo apt update
3. Finally, install the command line utility and graphical interface by running command:
sudo apt install ddcui ddcutil
Step 2: Control Screen Brightness via ddcui
After installing the tool, search for and launch it from either ‘Activities’ overview or start menu depends on your desktop environment.
When the tool opens, select your display (if more than one connected), and go to menu “View -> Features“. Finally, you’ll see the slide-bars for controlling brightness, contrast, GRB, etc.
NOTE: For permission issue, just open terminal (Ctrl+Alt+T) and run command to add your current user to i2c group, and finally restart computer:
sudo gpasswd --add $USER i2c
Uninstall ddcui & ddcutil
In case the tool does not support your display, remove it by running command in terminal:
sudo apt remove --autoremove ddcui ddcutil
Also, remove the Ubuntu PPA by running command:
sudo add-apt-repository --remove ppa:rockowitz/ddcutil
That’s all. Enjoy!