[i3] Setup brightness control with ddcutil

home/modules/i3+sway/default.nix

@@ -87,8 +87,8 @@ let
 
       "${shared_config.modifier}+r" = "mode resize";
 
-      "XF86MonBrightnessUp" = "exec brightnessctl s +5%";
-      "XF86MonBrightnessDown" = "exec brightnessctl s 5%-";
+      "XF86MonBrightnessUp" = "exec ddcutil setvcp 10 + 5";
+      "XF86MonBrightnessDown" = "exec ddcutil setvcp 10 - 5";
     };
   } cfg.extraSharedConfig;
 in {
@@ -149,11 +149,21 @@ in {
 
       [backlight]
       command=${pkgs.writeShellScript "i3blocks-backlight" ''
-        if command -v brightnessctl &>/dev/null; then
-          brightnessctl g | awk -v max=$(brightnessctl m) '{printf "☀️ %.0f%%\n", ($1/max)*100}'
+        if command -v ddcutil &>/dev/null; then
+          # Handle mouse scroll events
+          case $BLOCK_BUTTON in
+            4) ddcutil setvcp 10 + 5 ;;  # Scroll up - increase brightness
+            5) ddcutil setvcp 10 - 5 ;;  # Scroll down - decrease brightness
+          esac
+
+          # Display current brightness
+          brightness=$(ddcutil getvcp 10 2>/dev/null | grep -oP 'current value =\s*\K\d+')
+          if [ -n "$brightness" ]; then
+            echo "☀️ $brightness%"
+          fi
         fi
       ''}
-      interval=1
+      interval=5
       separator=true
 
       [network]

roles/desktop/x11.nix

@@ -19,8 +19,20 @@ in
           polkit_gnome                    # GNOME polkit authentication agent (more stable with i3)
           picom                           # Compositor for smooth rendering (important for Nvidia)
           networkmanagerapplet            # NetworkManager system tray applet
+          ddcutil                         # DDC/CI monitor control for brightness
         ];
       };
     };
+
+    # Enable DDC/CI support for monitor brightness control
+    boot.kernelModules = [ "i2c-dev" ];
+
+    # Add ddcutil udev rules and user permissions
+    hardware.i2c.enable = true;
+
+    # Install ddcutil system-wide
+    environment.systemPackages = with pkgs; [
+      ddcutil
+    ];
   };
 }