modules: BrightnessSlider - nwg-piotr/nwg-panel GitHub Wiki

Since v0.7.2 the brightness slider in the Controls module, apart from light and brightnessctl commands, also supports ddcutil, that allows to control external (not built-in) displays. However, having another Controls instance on each output would be a waste of resources. That's why we thought to add a separate tiny module, capable of using ddcutil.

You need to install ddcutil and give it all necessary permissions, following this guide. You may need to start i2c-dev in /etc/modules-load.d/i2c-dev.conf (or another location named in man modules-load.d).

Your monitor needs to support DDC/CI, and it must be enabled in monitor settings.