feat(void): backlight driver for external monitor

void.nix

@@ -1,6 +1,7 @@
 # Edit this configuration file to define what should be installed on
 # your system.  Help is available in the configuration.nix(5) man page
 # and in the NixOS manual (accessible by running ‘nixos-help’).
+{ config, ... }:
 {
   imports = [
     ./hardware-configuration-void.nix
@@ -37,4 +38,12 @@
     group = "music";
     isNormalUser = true;
   };
+
+  # enqble i2c-dev kernel module for control of backlight in external monitor
+  # https://discourse.nixos.org/t/how-to-enable-ddc-brightness-control-i2c-permissions/20800/3
+  boot.extraModulePackages = [
+    config.boot.kernelPackages.ddcci-driver
+  ];
+  boot.kernelModules = ["i2c-dev" "ddcci_backlight"];
+  hardware.i2c.enable = true;
 }