[i3] Setup brightness control with ddcutil

flake.nix

@@ -48,8 +48,8 @@
     nixosModules = [
       ./roles
     ] ++ [
+      ./roles/jovian-compat.nix
       inputs.home-manager.nixosModules.home-manager
-      inputs.jovian.nixosModules.jovian
       {
         nixpkgs.overlays = [
           (final: prev: {

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]

machines/zix790prors/configuration.nix

@@ -19,7 +19,6 @@ with lib;
       enable = true;
       gaming = {
         enable = true;
-        emulation = true;
       };
       kde = true;
       sddm = true;

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
+    ];
   };
 }

roles/jovian-compat.nix

@@ -1,8 +1,9 @@
 { lib, config, ... }:
 
-# Compatibility shim to provide services.logind.settings for NixOS 25.05
-# This allows Jovian-NixOS to work with stable NixOS
-# REMOVE THIS FILE when upgrading to NixOS 25.11 or later
+# Minimal Jovian compatibility layer for NixOS stable (25.05)
+# Defines only the Jovian options used by roles/desktop/steamos.nix
+# No actual implementation - just option definitions to prevent evaluation errors
+# REMOVE THIS FILE when all systems are on NixOS 25.11+ or unstable
 
 with lib;
 
@@ -11,10 +12,32 @@ let
   isCompatibleVersion = versionOlder nixosVersion "25.11";
 in
 {
-  options.services.logind.settings = mkOption {
-    type = types.attrsOf (types.attrsOf types.anything);
-    default = {};
-    description = "systemd-logind configuration. See logind.conf(5) for available options.";
+  options.jovian = {
+    steam = {
+      enable = mkEnableOption "Steam (jovian-compat stub)";
+
+      autoStart = mkOption {
+        type = types.bool;
+        default = false;
+        description = "Auto-start Steam (jovian-compat stub)";
+      };
+
+      user = mkOption {
+        type = types.str;
+        default = "user";
+        description = "Steam user (jovian-compat stub)";
+      };
+
+      desktopSession = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        description = "Desktop session (jovian-compat stub)";
+      };
+    };
+
+    decky-loader = {
+      enable = mkEnableOption "Decky Loader (jovian-compat stub)";
+    };
   };
 
   config = mkMerge [
@@ -25,19 +48,17 @@ in
           message = ''
             The Jovian compatibility shim (roles/jovian-compat.nix) is only needed for NixOS 25.05 and earlier.
             You are running NixOS ${nixosVersion}.
-            Please remove 'roles/jovian-compat.nix' from your flake.nix imports.
+            Please remove 'roles/jovian-compat.nix' from your flake.nix nixosModules list.
           '';
         }
       ];
     }
-    (mkIf (config.services.logind.settings != {}) {
-      # Convert the settings to extraConfig format for older NixOS
-      services.logind.extraConfig = let
-        mkSection = section: settings:
-          "[${section}]\n" +
-          (concatStringsSep "\n" (mapAttrsToList (k: v: "${k}=${toString v}") settings));
-      in
-        concatStringsSep "\n\n" (mapAttrsToList mkSection config.services.logind.settings);
+    # No config implementation - these options do nothing on stable systems
+    # steamos role is only enabled on nix-deck which uses unstable anyway
+    (mkIf config.jovian.steam.enable {
+      warnings = [
+        "Jovian is enabled but you're using the compatibility stub. This won't work correctly. Use NixOS unstable for Jovian support."
+      ];
     })
   ];
 }

roles/remote-build/default.nix

@@ -91,6 +91,11 @@ in
 
       users.groups.${cfg.builderUser} = {};
 
+      # Ensure home directory has correct permissions
+      systemd.tmpfiles.rules = [
+        "d /var/lib/${cfg.builderUser} 0700 ${cfg.builderUser} ${cfg.builderUser} -"
+      ];
+
       # Allow builder user to perform builds
       nix.settings.trusted-users = [ cfg.builderUser ];