{ pkgs, ... }:
{
  environment.systemPackages = with pkgs; [ brightnessctl ];

  services.udev.extraRules =
    let
      chgrp = "${pkgs.coreutils}/bin/chgrp";
      chmod = "${pkgs.coreutils}/bin/chmod";
    in
    ''
      ACTION=="add", SUBSYSTEM=="backlight", RUN+="${chgrp} video /sys/class/backlight/%k/brightness"
      ACTION=="add", SUBSYSTEM=="backlight", RUN+="${chmod} g+w   /sys/class/backlight/%k/brightness"
      ACTION=="add", SUBSYSTEM=="leds",      RUN+="${chgrp} input /sys/class/leds/%k/brightness"
      ACTION=="add", SUBSYSTEM=="leds",      RUN+="${chmod} g+w   /sys/class/leds/%k/brightness"
    '';
}