add monitor brightness control (#261)

Author: BNH440

modules/graphical/default.nix

@@ -189,6 +189,18 @@ in
           };
         };
 
+        systemd.user.services.brightness-reset = {
+          description = "Reset monitor brightness to 100% on logout";
+          partOf = [ "graphical-session.target" ];
+          wantedBy = [ "graphical-session.target" ];
+          serviceConfig = {
+            Type = "oneshot";
+            RemainAfterExit = true;
+            ExecStart = "${pkgs.coreutils}/bin/true";
+            ExecStop = "${pkgs.ddcutil}/bin/ddcutil setvcp 10 85";
+          };
+        };
+
         systemd.user.services.wayout = {
           description = "Automatic idle logout manager";
           after = [ "graphical-session.target" ];

profiles/desktop.nix

@@ -88,8 +88,16 @@ in
 
     # IRC password prompt
     kdePackages.kdialog
+
+    ddcutil # for monitor brightness control
   ];
 
+  # enable i2c and set udev rules for monitor brightness control
+  boot.kernelModules = [ "i2c-dev" ];
+  services.udev.extraRules = ''
+    KERNEL=="i2c-[0-9]*", RUN+="${pkgs.coreutils}/bin/chgrp 1000 /dev/%k", RUN+="${pkgs.coreutils}/bin/chmod 0660 /dev/%k"
+  '';
+
   services = {
     avahi.enable = true;