I am happy to announce that KDE Plasma 6.2 (released on 8 Oct. 2024) now features all functionality provided by this widget, and more. Since the Plasma implementation is a lot more robust and includes features that were planned but not yet implemented for this widget, I encourage all users of this project to use the official functionality once Plasma 6.2 is available in your distro.
The Plasma functionality is built into the Brightness and Colour Plasma widget, which can be enabled using the following steps:
Over the past few months I haven't had the time and motivation to work on this project. Moving forward, I’ve decided not to work on the niche use cases discussed in the issues and I won’t be working on this widget anymore.
Thank you all for your support - and a big thanks to the KDE developers for implementing this highly useful functionality!
ddcutil is a command line utility to control external monitors. We use ddcutil to detect supported monitors and adjust their brightness. For additional details, refer to the great ddcutil documentation. Note that additional steps may be required if you are using a NVIDIA GPU, see Special Nvidia Driver Settings in the ddcutil documentation.
Install the ddcutil
from your distribution's repositories. (Arch Linux)
By default, ddcutil can only be used the root user. Little configuration is required to allow non-root users to use it:
$ sudo usermod -aG i2c <username>
If the group i2c
doesn't exit, create it first:
$ sudo groupadd --system i2c
Finally, you need to install an udev rule to allow members of the group i2c
to access i²c devices:
$ sudo cp /usr/share/ddcutil/data/45-ddcutil-i2c.rules /etc/udev/rules.d
Rebooting your computer may be necessary for these rules to take effect. Now, you can verify that ddcutil is working correctly:
$ ddcutil detect
The output should look something like that:
Display 1
I2C bus: /dev/i2c-9
DRM connector: card0-DP-1
EDID synopsis:
Mfg id: DEL - Dell Inc.
Model: DELL S2721DGF
Product code: 16857 (0x41d9)
Serial number: XXXXXXXX
Binary serial number: XXXXXXXX (0xXXXXXXXX)
Manufacture year: 2022, Week: 35
VCP version: 2.1
Display 2
I2C bus: /dev/i2c-10
DRM connector: card0-DP-2
EDID synopsis:
Mfg id: DEL - Dell Inc.
Model: DELL U2417H
Product code: 16615 (0x40e7)
Serial number: XXXXXXXX
Binary serial number: XXXXXXXX (0xXXXXXXXX)
Manufacture year: 2018, Week: 22
VCP version: 2.1
If the output is the following:
No /dev/i2c devices exist.
ddcutil requires module i2c-dev.
the module is not compiled into the kernel, and you need to load the i2c_dev
kernel module.
Load it automatically during every boot:
$ echo i2c_dev | sudo tee /etc/modules-load.d/i2c_dev.conf
or load it once:
$ sudo modprobe i2c_dev
Install the backend from PyPI using the following command:
$ pip install --user ddcci-plasmoid-backend
You can also use pipx
to install the backend.
This is the recommended option if your distribution doesn't allow pip
for global packages, see PEP-668.
$ pipx install ddcci-plasmoid-backend
About pipx:
Overview: What is pipx?
pipx is a tool to help you install and run end-user applications written in Python. It's roughly similar to macOS's brew, JavaScript's npx, and Linux's apt.
It's closely related to pip. In fact, it uses pip, but is focused on installing and managing Python packages that can be run from the command line directly as applications.
How is it Different from pip?
pip is a general-purpose package installer for both libraries and apps with no environment isolation. pipx is made specifically for application installation, as it adds isolation yet still makes the apps available in your shell: pipx creates an isolated environment for each application and its associated packages.
Using the official package for KDE Plasma 6 or for KDE Plasma 5 from the KDE store is the recommended way to install this widget.
Alternatively, you can install the widget directly from this repopsitory:
$ git clone https://github.com/davidhi7/ddcci-plasmoid.git
$ cd ddcci-plasmoid
$ kpackagetool5 --install plasmoid
# or upgrade the plasmoid:
$ kpackagetool5 --upgrade plasmoid
Note that the main
branch is ported to KDE Plasma 6. To install the widget for Plasma 5, run git checkout kf5
before invoking kpackagetool5
.
[!IMPORTANT]
If you usedpipx
to install the backend in the previous step, the widget settingBackend executable command
must be set to~/.local/bin/ddcci_plasmoid_backend
(withoutpython3
or anything else before).
This widget can be displayed within the system tray or as a standalone widget.
Right-click the arrow of the system tray > open settings > go to Entries > scroll down to the entry Display Brightness and set the visibility according to your preference.
Right-click your desktop > click Add widgets > search for Display Brightness and add the widget to your desktop or panels.
pip
fails, printing This environment is externally managed
Some distributions, most notably Arch Linux, disable the installation of PyPI packages globally using pip
. In Step 3, use the pipx
alternative instead.
ddcutil detect
starts with Unable to open directory /sys/bus/i2c/devices/i2c--1: No such file or directory
This is a bug in older ddcutil versions which it is fixed in ddcutil v1.4.1. In some cases, it may cause the backend to fail.
VCP version
detection failed by ddcutil (#39)First public release