DeviceManager: use gala's brightness interface

src/Indicator.vala

@@ -30,6 +30,7 @@ public class Power.Indicator : Wingpanel.Indicator {
 
     private Services.Device? display_device = null;
     private Services.DeviceManager dm;
+    private Services.BrightnessManager brightness_manager;
 
     private Settings settings;
 
@@ -46,6 +47,7 @@ public class Power.Indicator : Wingpanel.Indicator {
         Gtk.IconTheme.get_for_display (Gdk.Display.get_default ()).add_resource_path ("/io/elementary/panel/power");
 
         dm = Power.Services.DeviceManager.get_default ();
+        brightness_manager = Services.BrightnessManager.get_default ();
 
         var mouse_settings = new GLib.Settings ("org.gnome.desktop.peripherals.mouse");
         mouse_settings.bind ("natural-scroll", this, "natural-scroll-mouse", SettingsBindFlags.DEFAULT);
@@ -60,35 +62,14 @@ public class Power.Indicator : Wingpanel.Indicator {
             display_widget = new Widgets.DisplayWidget ();
 
             /* No need to display the indicator when the device is completely in AC mode */
-            if (dm.has_battery || dm.backlight.present) {
+            if (dm.has_battery || brightness_manager.present) {
                 update_visibility ();
             }
 
             dm.notify["has-battery"].connect (update_visibility);
             dm.notify["display-device"].connect (update_display_device);
             settings.changed["show-percentage"].connect (update_tooltip);
-
-            if (dm.backlight.present) {
-                var scroll_controller = new Gtk.EventControllerScroll (BOTH_AXES);
-                scroll_controller.scroll.connect ((controller, dx, dy) => {
-                    if (Utils.handle_scroll_event (
-                            (Gdk.ScrollEvent) controller.get_current_event (),
-                            natural_scroll_mouse,
-                            natural_scroll_touchpad)
-                    ) {
-                        if (popover_widget == null || !popover_widget.is_visible ()) {
-                          show_notification ();
-                        }
-
-                        return true;
-                    }
-
-                    return false;
-                });
-                display_widget.add_controller (scroll_controller);
-
-                dm.brightness_changed.connect (update_tooltip);
-            }
+            brightness_manager.connected.connect (update_scroll_controller);
         }
 
         return display_widget;
@@ -111,7 +92,7 @@ public class Power.Indicator : Wingpanel.Indicator {
     private void update_visibility () {
         var dm = Services.DeviceManager.get_default ();
 
-        bool should_be_visible = (dm.has_battery || dm.backlight.present);
+        bool should_be_visible = (dm.has_battery || brightness_manager.present);
         if (visible != should_be_visible) {
             /* NOTE: popover closes every time you set visibility, so change property only when needed */
             visible = should_be_visible;
@@ -190,8 +171,8 @@ public class Power.Indicator : Wingpanel.Indicator {
             }
         }
 
-        if (primary_text == null && dm.backlight.present) {
-            primary_text = _("Screen brightness: %i").printf ((int)(dm.brightness));
+        if (primary_text == null && brightness_manager.present) {
+            primary_text = _("Screen brightness: %i").printf ((int) (brightness_manager.get_global_brightness () * 100));
             secondary_text = _("Scroll to change screen brightness");
         }
 
@@ -211,7 +192,7 @@ public class Power.Indicator : Wingpanel.Indicator {
         if (is_in_session) {
             var notification = new Notify.Notification ("indicator-power", "", "display-brightness-symbolic");
             notification.set_hint ("x-canonical-private-synchronous", new Variant.string ("indicator-power"));
-            notification.set_hint ("value", new Variant.int32 (dm.brightness));
+            notification.set_hint ("value", new Variant.int32 ((int) (brightness_manager.get_global_brightness () * 100)));
             try {
                 notification.show ();
                 return true;
@@ -223,6 +204,30 @@ public class Power.Indicator : Wingpanel.Indicator {
 
         return false;
     }
+
+    private void update_scroll_controller () {
+        if (brightness_manager.present) {
+            var scroll_controller = new Gtk.EventControllerScroll (BOTH_AXES);
+            scroll_controller.scroll.connect ((controller, dx, dy) => {
+                if (Utils.handle_global_scroll_event (
+                        (Gdk.ScrollEvent) controller.get_current_event (),
+                        natural_scroll_mouse,
+                        natural_scroll_touchpad)
+                ) {
+                    if (popover_widget == null || !popover_widget.is_visible ()) {
+                      show_notification ();
+                    }
+
+                    return true;
+                }
+
+                return false;
+            });
+            display_widget.add_controller (scroll_controller);
+
+            brightness_manager.monitor_brightness_changed.connect (update_tooltip);
+        }
+    }
 }
 
 public Wingpanel.Indicator get_indicator (Module module, Wingpanel.IndicatorManager.ServerType server_type) {

src/Services/BrightnessManager.vala

@@ -0,0 +1,128 @@
+/*
+ * Copyright 2026 elementary, Inc. (https://elementary.io)
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ * Authored by: Denis Garaev <garaevdi@outlook.com>
+ */
+
+public class Power.Services.BrightnessManager : Object {
+    private const string GALA_INTERFACE = "io.elementary.gala";
+    private const string GALA_PATH = "/io/elementary/gala/BrightnessManager";
+
+    public signal void connected ();
+    public signal void monitors_changed ();
+    public signal void monitor_brightness_changed (int index, double value);
+
+    private Power.Services.DBusInterfaces.GalaBrightnessManager? gala_brightness_manager;
+
+    private static BrightnessManager? instance = null;
+
+    public bool present {
+        get {
+            if (gala_brightness_manager == null) {
+                return false;
+            }
+
+            try {
+                if (gala_brightness_manager.get_n_monitors () == 0) {
+                    return false;
+                }
+            } catch {}
+
+            return true;
+        }
+    }
+
+    construct {
+        init.begin ((obj, res) => {
+            try {
+                init.end (res);
+                connect_signals ();
+            } catch {}
+        });
+    }
+
+    public static Power.Services.BrightnessManager get_default () {
+        if (instance == null) {
+            instance = new BrightnessManager ();
+        }
+
+        return instance;
+    }
+
+    public int get_n_monitors () {
+        try {
+            return gala_brightness_manager.get_n_monitors ();
+        } catch (Error e) {
+            warning ("Couldn't get number of monitors: %s", e.message);
+            return -1;
+        }
+    }
+
+    public double get_global_brightness () {
+        try {
+            return gala_brightness_manager.get_global_brightness ().clamp (0.0001, 1.0);
+        } catch (Error e) {
+            warning ("Couldn't get global brightness: %s", e.message);
+            return -1.0f;
+        }
+    }
+
+    public void set_global_brightness (double value) {
+        try {
+            gala_brightness_manager.set_global_brightness (value.clamp (0.0001, 1.0));
+        } catch (Error e) {
+            warning ("Coulnd't set global brightness: %s", e.message);
+        }
+    }
+
+    public string get_monitor_name (int index) {
+        try {
+            return gala_brightness_manager.get_monitor_name (index);
+        } catch (Error e) {
+            warning ("Couldn't get %n monitor's name: %s", index, e.message);
+            return "";
+        }
+    }
+
+    public double get_monitor_brightness (int index) {
+        try {
+            return gala_brightness_manager.get_monitor_brightness (index).clamp (0.0001, 1);
+        } catch (Error e) {
+            warning ("Couldn't get %n monitor's brightness: %s", index, e.message);
+            return -1.0f;
+        }
+    }
+
+    public void set_monitor_brightness (int index, double value) {
+        try {
+            gala_brightness_manager.set_monitor_brightness (index, value.clamp (0.0001, 1));
+        } catch (Error e) {
+            warning ("Coulnd't set %n monitor's brightness: %s", index, e.message);
+        }
+    }
+
+
+    private async void init () throws Error {
+        try {
+            gala_brightness_manager = yield Bus.get_proxy (BusType.SESSION, GALA_INTERFACE, GALA_PATH);
+            connected ();
+        } catch (Error e) {
+            warning ("Couldn't connect to Gala's BrightnessManager: %s", e.message);
+            throw e;
+        }
+    }
+
+    private void connect_signals () {
+        gala_brightness_manager.monitors_changed.connect (on_monitors_changed);
+        gala_brightness_manager.monitor_brightness_changed.connect (on_monitor_brightness_changed);
+    }
+
+    private void on_monitors_changed () {
+        monitors_changed ();
+    }
+
+    private void on_monitor_brightness_changed (int index, double value) {
+        monitor_brightness_changed (index, value);
+    }
+}

src/Services/DBusInterfaces/Screen.vala → src/Services/DBusInterfaces/GalaBrightnessManager.vala

@@ -18,8 +18,16 @@
  */
 
 namespace Power.Services.DBusInterfaces {
-  [DBus (name = "org.gnome.SettingsDaemon.Power.Screen")]
-  interface PowerSettings : GLib.Object {
-    public abstract int brightness { get; set; }
+  [DBus (name = "io.elementary.gala.BrightnessManager")]
+  interface GalaBrightnessManager : GLib.Object {
+    public signal void monitors_changed ();
+    public signal void monitor_brightness_changed (int index, double value);
+
+    public abstract double get_global_brightness () throws GLib.IOError, GLib.DBusError;
+    public abstract double get_monitor_brightness (int index) throws GLib.IOError, GLib.DBusError;
+    public abstract string get_monitor_name (int index) throws GLib.IOError, GLib.DBusError;
+    public abstract int get_n_monitors () throws GLib.IOError, GLib.DBusError;
+    public abstract void set_global_brightness (double scale) throws GLib.IOError, GLib.DBusError;
+    public abstract void set_monitor_brightness (int index, double brightness) throws GLib.IOError, GLib.DBusError;
   }
 }