External monitor brightnessctl support requires ddcci-driver-linux driver

[blacklightpy]

This could be added to the guide.

[blacklightpy]

The DDC/CI driver (ddcci-linux) is meant to be installed with DKMS. However the master branch only supports upto kernel 6.4 as of now. This driver provides backlight interfaces for external monitors in /sys/class/backlight, which will make userspace brightness control utilities work.

As an alternative, i2c_dev module can be loaded to enable an interface to the monitor, through which the tool ddcutil can communicate to the DDC/CI address.

Anyways hope this helps someone. My monitor had terrible display at other brightness values, so it didn't help me 🙁

[vicentelyrio]

I have success using https://aur.archlinux.org/packages/ddcci-driver-linux-dkms-git with 6.9 kernel