power: Refactor brightness scale code into a CcBrightnessScale class

This reduces some redundancy between the screen brightness and keyboard
brightness code.

Such refactoring is a prerequisite for including a keyboard backlight
control in the Keyboard panel, as has been [proposed][1]. But hopefully
this makes the code a bit neater and more managable even without that.

[1]: https://gitlab.gnome.org/Teams/Design/settings-mockups/-/blob/master/keyboard/Keyboard-with-dialogs.png

4 files changed, 372 insertions, 243 deletions

diff --git a/panels/power/cc-brightness-scale.c b/panels/power/cc-brightness-scale.c
new file mode 100644
index 000000000..517177771
--- /dev/null
+++ b/panels/power/cc-brightness-scale.c
@@ -0,0 +1,282 @@
+/* cc-brightness-scale.c
+ *
+ * Copyright (C) 2010 Red Hat, Inc
+ * Copyright (C) 2008 William Jon McCann <jmccann@redhat.com>
+ * Copyright (C) 2010,2015 Richard Hughes <richard@hughsie.com>
+ * Copyright (C) 2020 System76, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "cc-brightness-scale.h"
+#include "shell/cc-object-storage.h"
+
+struct _CcBrightnessScale {
+  GtkScale         parent_instance;
+
+  GCancellable    *cancellable;
+  BrightnessDevice device;
+  gboolean         has_brightness;
+  GDBusProxy      *proxy;
+  gboolean         setting_brightness;
+};
+
+enum
+{
+  PROP_0,
+  PROP_HAS_BRIGHTNESS,
+  PROP_DEVICE,
+};
+
+G_DEFINE_TYPE (CcBrightnessScale, cc_brightness_scale, GTK_TYPE_SCALE)
+
+static void
+set_brightness_cb (GObject *source_object, GAsyncResult *res, gpointer user_data)
+{
+  g_autoptr(GError) error = NULL;
+  g_autoptr(GVariant) result = NULL;
+  GDBusProxy *proxy = G_DBUS_PROXY (source_object);
+
+  result = g_dbus_proxy_call_finish (proxy, res, &error);
+  if (result == NULL)
+    {
+      if (!g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
+        g_printerr ("Error setting brightness: %s\n", error->message);
+      return;
+    }
+
+  CcBrightnessScale *self = CC_BRIGHTNESS_SCALE (user_data);
+
+  /* not setting, so pay attention to changed signals */
+  self->setting_brightness = FALSE;
+}
+
+static void
+brightness_slider_value_changed_cb (CcBrightnessScale *self, GtkRange *range)
+{
+  guint percentage;
+  g_autoptr(GVariant) variant = NULL;
+
+  percentage = (guint) gtk_range_get_value (range);
+
+  /* do not loop */
+  if (self->setting_brightness)
+    return;
+
+  self->setting_brightness = TRUE;
+
+  if (self->device == BRIGHTNESS_DEVICE_KBD)
+    variant = g_variant_new_parsed ("('org.gnome.SettingsDaemon.Power.Keyboard',"
+                                    "'Brightness', %v)",
+                                    g_variant_new_int32 (percentage));
+  else
+    variant = g_variant_new_parsed ("('org.gnome.SettingsDaemon.Power.Screen',"
+                                    "'Brightness', %v)",
+                                    g_variant_new_int32 (percentage));
+
+  /* push this to g-s-d */
+  g_dbus_proxy_call (self->proxy,
+                     "org.freedesktop.DBus.Properties.Set",
+                     g_variant_ref_sink (variant),
+                     G_DBUS_CALL_FLAGS_NONE,
+                     -1,
+                     self->cancellable,
+                     set_brightness_cb,
+                     self);
+}
+
+static void
+sync_brightness (CcBrightnessScale *self)
+{
+  g_autoptr(GVariant) result = NULL;
+  gint brightness;
+  GtkRange *range;
+
+  result = g_dbus_proxy_get_cached_property (self->proxy, "Brightness");
+
+  if (result)
+    {
+      /* set the slider */
+      brightness = g_variant_get_int32 (result);
+      self->has_brightness = brightness >= 0.0;
+    }
+  else
+    {
+      self->has_brightness = FALSE;
+    }
+
+  g_object_notify (G_OBJECT (self), "has-brightness");
+
+  if (self->has_brightness)
+    {
+      range = GTK_RANGE (self);
+      self->setting_brightness = TRUE;
+      gtk_range_set_value (range, brightness);
+      self->setting_brightness = FALSE;
+    }
+}
+
+static void
+got_proxy_cb (GObject *source_object, GAsyncResult *res, gpointer user_data)
+{
+  g_autoptr(GError) error = NULL;
+  CcBrightnessScale *self;
+  GDBusProxy *proxy;
+
+  self = CC_BRIGHTNESS_SCALE (user_data);
+
+  proxy = cc_object_storage_create_dbus_proxy_finish (res, &error);
+  if (proxy == NULL)
+    {
+      if (!g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
+        g_printerr ("Error creating proxy: %s\n", error->message);
+      return;
+    }
+
+  self->proxy = proxy;
+
+  g_signal_connect_object (proxy, "g-properties-changed",
+                           G_CALLBACK (sync_brightness), self, G_CONNECT_SWAPPED);
+
+  sync_brightness (self);
+}
+
+static void
+cc_brightness_scale_get_property (GObject    *object,
+                                  guint       prop_id,
+                                  GValue     *value,
+                                  GParamSpec *pspec)
+{
+  CcBrightnessScale *self;
+
+  self = CC_BRIGHTNESS_SCALE (object);
+
+  switch (prop_id) {
+  case PROP_HAS_BRIGHTNESS:
+    g_value_set_boolean (value, self->has_brightness);
+    break;
+  default:
+    G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    break;
+  }
+}
+
+static void
+cc_brightness_scale_set_property (GObject      *object,
+                                  guint         prop_id,
+                                  const GValue *value,
+                                  GParamSpec   *pspec)
+{
+  CcBrightnessScale *self;
+
+  self = CC_BRIGHTNESS_SCALE (object);
+
+  switch (prop_id) {
+  case PROP_DEVICE:
+    self->device = g_value_get_enum (value);
+    break;
+  default:
+    G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    break;
+  }
+}
+
+static void
+cc_brightness_scale_constructed (GObject *object)
+{
+  CcBrightnessScale *self;
+  const gchar *interface;
+
+  G_OBJECT_CLASS (cc_brightness_scale_parent_class)->constructed (object);
+
+  self = CC_BRIGHTNESS_SCALE (object);
+
+  self->cancellable = g_cancellable_new();
+
+  g_signal_connect_object (GTK_SCALE (self), "value-changed",
+                           G_CALLBACK (brightness_slider_value_changed_cb), self, G_CONNECT_SWAPPED);
+
+  if (self->device == BRIGHTNESS_DEVICE_KBD)
+    interface = "org.gnome.SettingsDaemon.Power.Keyboard";
+  else
+    interface = "org.gnome.SettingsDaemon.Power.Screen";
+
+  cc_object_storage_create_dbus_proxy (G_BUS_TYPE_SESSION,
+                                       G_DBUS_PROXY_FLAGS_NONE,
+                                       "org.gnome.SettingsDaemon.Power",
+                                       "/org/gnome/SettingsDaemon/Power",
+                                       interface,
+                                       self->cancellable,
+                                       got_proxy_cb,
+                                       self);
+
+  gtk_range_set_range (GTK_RANGE (self), 0, 100);
+  gtk_range_set_increments (GTK_RANGE (self), 1, 10);
+  gtk_range_set_round_digits (GTK_RANGE (self), 0);
+  gtk_scale_set_draw_value (GTK_SCALE (self), FALSE);
+}
+
+static void
+cc_brightness_scale_finalize (GObject *object)
+{
+  CcBrightnessScale *self = CC_BRIGHTNESS_SCALE (object);
+
+  g_cancellable_cancel (self->cancellable);
+
+  G_OBJECT_CLASS (cc_brightness_scale_parent_class)->finalize (object);
+}
+
+void
+cc_brightness_scale_class_init (CcBrightnessScaleClass *klass)
+{
+  GObjectClass  *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->get_property = cc_brightness_scale_get_property;
+  object_class->set_property = cc_brightness_scale_set_property;
+  object_class->constructed = cc_brightness_scale_constructed;
+  object_class->finalize = cc_brightness_scale_finalize;
+
+  g_object_class_install_property (object_class,
+                                   PROP_DEVICE,
+                                   g_param_spec_enum ("device",
+                                                      "device",
+                                                      "device",
+                                                      brightness_device_get_type(),
+                                                      BRIGHTNESS_DEVICE_SCREEN,
+                                                      G_PARAM_CONSTRUCT_ONLY | G_PARAM_WRITABLE));
+
+  g_object_class_install_property (object_class,
+                                   PROP_HAS_BRIGHTNESS,
+                                   g_param_spec_boolean ("has-brightness",
+                                                         "has brightness",
+                                                         "has brightness",
+                                                         FALSE,
+                                                         G_PARAM_READABLE));
+}
+
+static void
+cc_brightness_scale_init (CcBrightnessScale *self)
+{
+}
+
+
+gboolean
+cc_brightness_scale_get_has_brightness (CcBrightnessScale *self)
+{
+  g_return_val_if_fail (CC_IS_BRIGHTNESS_SCALE (self), FALSE);
+
+  return self->has_brightness;
+}
diff --git a/panels/power/cc-brightness-scale.h b/panels/power/cc-brightness-scale.h
new file mode 100644
index 000000000..b55d05b33
--- /dev/null
+++ b/panels/power/cc-brightness-scale.h
@@ -0,0 +1,38 @@
+/* cc-brightness-scale.h
+ *
+ * Copyright (C) 2020 System76, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#pragma once
+
+#include <gtk/gtk.h>
+#include "cc-brightness-scale-types.h"
+
+G_BEGIN_DECLS
+
+typedef enum {
+    BRIGHTNESS_DEVICE_SCREEN,
+    BRIGHTNESS_DEVICE_KBD,
+} BrightnessDevice;
+
+#define CC_TYPE_BRIGHTNESS_SCALE (cc_brightness_scale_get_type())
+G_DECLARE_FINAL_TYPE (CcBrightnessScale, cc_brightness_scale, CC, BRIGHTNESS_SCALE, GtkBox)
+
+gboolean cc_brightness_scale_get_has_brightness (CcBrightnessScale*);
+
+G_END_DECLS
diff --git a/panels/power/cc-power-panel.c b/panels/power/cc-power-panel.c
index e565ee934..044f633f9 100644
--- a/panels/power/cc-power-panel.c
+++ b/panels/power/cc-power-panel.c
@@ -31,6 +31,7 @@
 
 #include "shell/cc-object-storage.h"
 #include "list-box-helper.h"
+#include "cc-brightness-scale.h"
 #include "cc-power-panel.h"
 #include "cc-power-resources.h"
 #include "cc-util.h"
@@ -75,8 +76,6 @@ struct _CcPowerPanel
   GtkListStore  *liststore_power_button;
   UpClient      *up_client;
   GPtrArray     *devices;
-  GDBusProxy    *screen_proxy;
-  GDBusProxy    *kbd_proxy;
   gboolean       has_batteries;
   char          *chassis_type;
 
@@ -99,11 +98,9 @@ struct _CcPowerPanel
 
   GtkWidget     *dim_screen_row;
   GtkWidget     *brightness_row;
-  GtkWidget     *brightness_scale;
-  gboolean       setting_brightness;
+  CcBrightnessScale *brightness_scale;
   GtkWidget     *kbd_brightness_row;
-  GtkWidget     *kbd_brightness_scale;
-  gboolean       kbd_setting_brightness;
+  CcBrightnessScale *kbd_brightness_scale;
 
   GtkWidget     *automatic_suspend_row;
   GtkWidget     *automatic_suspend_label;
@@ -150,8 +147,6 @@ cc_power_panel_dispose (GObject *object)
   g_clear_object (&self->session_settings);
   g_clear_object (&self->interface_settings);
   g_clear_pointer (&self->automatic_suspend_dialog, gtk_widget_destroy);
-  g_clear_object (&self->screen_proxy);
-  g_clear_object (&self->kbd_proxy);
   g_clear_pointer (&self->devices, g_ptr_array_unref);
   g_clear_object (&self->up_client);
   g_clear_object (&self->bt_rfkill);
@@ -1035,144 +1030,6 @@ up_client_device_added (CcPowerPanel *self,
 }
 
 static void
-set_brightness_cb (GObject *source_object, GAsyncResult *res, gpointer user_data)
-{
-  CcPowerPanel *self = CC_POWER_PANEL (user_data);
-  g_autoptr(GError) error = NULL;
-  g_autoptr(GVariant) result = NULL;
-  GDBusProxy *proxy = G_DBUS_PROXY (source_object);
-
-  /* not setting, so pay attention to changed signals */
-  if (proxy == self->screen_proxy)
-    self->setting_brightness = FALSE;
-  else if (proxy == self->kbd_proxy)
-    self->kbd_setting_brightness = FALSE;
-
-  result = g_dbus_proxy_call_finish (proxy, res, &error);
-  if (result == NULL)
-    {
-      if (!g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
-        g_printerr ("Error setting brightness: %s\n", error->message);
-      return;
-    }
-}
-
-static void
-brightness_slider_value_changed_cb (CcPowerPanel *self, GtkRange *range)
-{
-  guint percentage;
-  g_autoptr(GVariant) variant = NULL;
-  GDBusProxy *proxy;
-
-  percentage = (guint) gtk_range_get_value (range);
-
-  if (range == GTK_RANGE (self->brightness_scale))
-    {
-      /* do not loop */
-      if (self->setting_brightness)
-        return;
-
-      self->setting_brightness = TRUE;
-      proxy = self->screen_proxy;
-
-      variant = g_variant_new_parsed ("('org.gnome.SettingsDaemon.Power.Screen',"
-                                      "'Brightness', %v)",
-                                      g_variant_new_int32 (percentage));
-    }
-  else
-    {
-      /* do not loop */
-      if (self->kbd_setting_brightness)
-        return;
-
-      self->kbd_setting_brightness = TRUE;
-      proxy = self->kbd_proxy;
-
-      variant = g_variant_new_parsed ("('org.gnome.SettingsDaemon.Power.Keyboard',"
-                                      "'Brightness', %v)",
-                                      g_variant_new_int32 (percentage));
-    }
-
-  /* push this to g-s-d */
-  g_dbus_proxy_call (proxy,
-                     "org.freedesktop.DBus.Properties.Set",
-                     g_variant_ref_sink (variant),
-                     G_DBUS_CALL_FLAGS_NONE,
-                     -1,
-                     cc_panel_get_cancellable (CC_PANEL (self)),
-                     set_brightness_cb,
-                     self);
-}
-
-static void
-sync_kbd_brightness (CcPowerPanel *self)
-{
-  g_autoptr(GVariant) result = NULL;
-  gint brightness;
-  gboolean visible;
-  GtkRange *range;
-
-  result = g_dbus_proxy_get_cached_property (self->kbd_proxy, "Brightness");
-  if (result)
-    {
-      /* set the slider */
-      brightness = g_variant_get_int32 (result);
-      visible = brightness >= 0.0;
-    }
-  else
-    {
-      visible = FALSE;
-    }
-
-  gtk_widget_set_visible (self->kbd_brightness_row, visible);
-
-  if (visible)
-    {
-      range = GTK_RANGE (self->kbd_brightness_scale);
-      gtk_range_set_range (range, 0, 100);
-      gtk_range_set_increments (range, 1, 10);
-      self->kbd_setting_brightness = TRUE;
-      gtk_range_set_value (range, brightness);
-      self->kbd_setting_brightness = FALSE;
-    }
-}
-
-static void
-sync_screen_brightness (CcPowerPanel *self)
-{
-  g_autoptr(GVariant) result = NULL;
-  gint brightness;
-  gboolean visible;
-  GtkRange *range;
-
-  result = g_dbus_proxy_get_cached_property (self->screen_proxy, "Brightness");
-
-  if (result)
-    {
-      /* set the slider */
-      brightness = g_variant_get_int32 (result);
-      visible = brightness >= 0.0;
-    }
-  else
-    {
-      visible = FALSE;
-    }
-
-  gtk_widget_set_visible (self->brightness_row, visible);
-  gtk_widget_set_visible (self->dim_screen_row, visible);
-
-  if (visible)
-    {
-      range = GTK_RANGE (self->brightness_scale);
-      gtk_range_set_range (range, 0, 100);
-      gtk_range_set_increments (range, 1, 10);
-      self->setting_brightness = TRUE;
-      gtk_range_set_value (range, brightness);
-      self->setting_brightness = FALSE;
-    }
-}
-
-static void
 als_switch_changed (CcPowerPanel *self)
 {
   gboolean enabled;
@@ -1188,12 +1045,7 @@ als_enabled_state_changed (CcPowerPanel *self)
   gboolean has_brightness = FALSE;
   gboolean visible = FALSE;
 
-  if (self->screen_proxy != NULL)
-    {
-      g_autoptr(GVariant) v = g_dbus_proxy_get_cached_property (self->screen_proxy, "Brightness");
-      if (v != NULL)
-        has_brightness = g_variant_get_int32 (v) >= 0.0;
-    }
+  has_brightness = cc_brightness_scale_get_has_brightness (self->brightness_scale);
 
   if (self->iio_proxy != NULL)
     {
@@ -1211,69 +1063,6 @@ als_enabled_state_changed (CcPowerPanel *self)
 }
 
 static void
-on_screen_property_change (CcPowerPanel *self)
-{
-  sync_screen_brightness (self);
-}
-
-static void
-got_screen_proxy_cb (GObject *source_object, GAsyncResult *res, gpointer user_data)
-{
-  g_autoptr(GError) error = NULL;
-  CcPowerPanel *self;
-  GDBusProxy *screen_proxy;
-
-  screen_proxy = cc_object_storage_create_dbus_proxy_finish (res, &error);
-  if (screen_proxy == NULL)
-    {
-      if (!g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
-        g_printerr ("Error creating screen proxy: %s\n", error->message);
-      return;
-    }
-
-  self = CC_POWER_PANEL (user_data);
-  self->screen_proxy = screen_proxy;
-
-  /* we want to change the bar if the user presses brightness buttons */
-  g_signal_connect_object (screen_proxy, "g-properties-changed",
-                           G_CALLBACK (on_screen_property_change), self, G_CONNECT_SWAPPED);
-
-  sync_screen_brightness (self);
-  als_enabled_state_changed (self);
-}
-
-static void
-on_kbd_property_change (CcPowerPanel *self)
-{
-  sync_kbd_brightness (self);
-}
-
-static void
-got_kbd_proxy_cb (GObject *source_object, GAsyncResult *res, gpointer user_data)
-{
-  CcPowerPanel *self;
-  g_autoptr(GError) error = NULL;
-  GDBusProxy *kbd_proxy;
-
-  kbd_proxy = cc_object_storage_create_dbus_proxy_finish (res, &error);
-  if (kbd_proxy == NULL)
-    {
-      if (!g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
-        g_printerr ("Error creating keyboard proxy: %s\n", error->message);
-      return;
-    }
-
-  self = CC_POWER_PANEL (user_data);
-  self->kbd_proxy = kbd_proxy;
-
-  /* we want to change the bar if the user presses brightness buttons */
-  g_signal_connect_object (kbd_proxy, "g-properties-changed",
-                           G_CALLBACK (on_kbd_property_change), self, G_CONNECT_SWAPPED);
-
-  sync_kbd_brightness (self);
-}
-
-static void
 combo_time_changed_cb (CcPowerPanel *self, GtkWidget *widget)
 {
   GtkTreeIter iter;
@@ -1739,9 +1528,10 @@ combo_power_button_changed_cb (CcPowerPanel *self)
 }
 
 static GtkWidget *
-add_brightness_row (CcPowerPanel  *self,
-		    const char    *text,
-		    GtkWidget    **brightness_scale)
+add_brightness_row (CcPowerPanel       *self,
+                    BrightnessDevice    device,
+		    const char         *text,
+		    CcBrightnessScale **brightness_scale)
 {
   GtkWidget *row, *box, *label, *title, *box2, *w, *scale;
 
@@ -1759,15 +1549,14 @@ add_brightness_row (CcPowerPanel  *self,
   gtk_box_pack_start (GTK_BOX (box2), w, FALSE, TRUE, 0);
   gtk_size_group_add_widget (self->charge_sizegroup, w);
 
-  *brightness_scale = scale = gtk_scale_new_with_range (GTK_ORIENTATION_HORIZONTAL, 0, 100, 1);
+  scale = g_object_new (CC_TYPE_BRIGHTNESS_SCALE,
+                        "device", device,
+                        NULL);
   gtk_widget_show (scale);
   gtk_label_set_mnemonic_widget (GTK_LABEL (label), scale);
-  gtk_scale_set_draw_value (GTK_SCALE (scale), FALSE);
   gtk_box_pack_start (GTK_BOX (box2), scale, TRUE, TRUE, 0);
   gtk_size_group_add_widget (self->level_sizegroup, scale);
-  gtk_range_set_round_digits (GTK_RANGE (scale), 0);
-  g_signal_connect_object (scale, "value-changed",
-                           G_CALLBACK (brightness_slider_value_changed_cb), self, G_CONNECT_SWAPPED);
+  *brightness_scale = CC_BRIGHTNESS_SCALE (scale);
 
   gtk_box_pack_start (GTK_BOX (box), box2, TRUE, TRUE, 0);
 
@@ -2009,6 +1798,32 @@ can_suspend_or_hibernate (CcPowerPanel *self,
 }
 
 static void
+has_brightness_cb (CcPowerPanel *self)
+{
+  gboolean has_brightness;
+
+  has_brightness = cc_brightness_scale_get_has_brightness (self->brightness_scale);
+
+  gtk_widget_set_visible (self->brightness_row, has_brightness);
+  gtk_widget_set_visible (self->dim_screen_row, has_brightness);
+
+  als_enabled_state_changed (self);
+
+}
+
+static void
+has_kbd_brightness_cb (CcPowerPanel *self,
+                       GParamSpec   *pspec,
+                       GObject      *object)
+{
+  gboolean has_brightness;
+
+  has_brightness = cc_brightness_scale_get_has_brightness (self->kbd_brightness_scale);
+
+  gtk_widget_set_visible (self->kbd_brightness_row, has_brightness);
+}
+
+static void
 add_power_saving_section (CcPowerPanel *self)
 {
   GtkWidget *widget, *box, *label, *row;
@@ -2054,7 +1869,9 @@ add_power_saving_section (CcPowerPanel *self)
   gtk_container_add (GTK_CONTAINER (box), widget);
   gtk_box_pack_start (GTK_BOX (self->vbox_power), box, FALSE, TRUE, 0);
 
-  row = add_brightness_row (self, _("_Screen Brightness"), &self->brightness_scale);
+  row = add_brightness_row (self, BRIGHTNESS_DEVICE_SCREEN, _("_Screen Brightness"), &self->brightness_scale);
+  g_signal_connect_object (self->brightness_scale, "notify::has-brightness",
+                           G_CALLBACK (has_brightness_cb), self, G_CONNECT_SWAPPED);
   gtk_widget_show (row);
   self->brightness_row = row;
 
@@ -2088,7 +1905,9 @@ add_power_saving_section (CcPowerPanel *self)
   g_signal_connect_object (self->als_switch, "notify::active",
                            G_CALLBACK (als_switch_changed), self, G_CONNECT_SWAPPED);
 
-  row = add_brightness_row (self, _("_Keyboard Brightness"), &self->kbd_brightness_scale);
+  row = add_brightness_row (self, BRIGHTNESS_DEVICE_KBD, _("_Keyboard Brightness"), &self->kbd_brightness_scale);
+  g_signal_connect_object (self->kbd_brightness_scale, "notify::has-brightness",
+                           G_CALLBACK (has_kbd_brightness_cb), self, G_CONNECT_SWAPPED);
   gtk_widget_show (row);
   self->kbd_brightness_row = row;
 
@@ -2548,23 +2367,6 @@ cc_power_panel_init (CcPowerPanel *self)
   gtk_widget_init_template (GTK_WIDGET (self));
   load_custom_css (self);
 
-  cc_object_storage_create_dbus_proxy (G_BUS_TYPE_SESSION,
-                                       G_DBUS_PROXY_FLAGS_NONE,
-                                       "org.gnome.SettingsDaemon.Power",
-                                       "/org/gnome/SettingsDaemon/Power",
-                                       "org.gnome.SettingsDaemon.Power.Screen",
-                                       cc_panel_get_cancellable (CC_PANEL (self)),
-                                       got_screen_proxy_cb,
-                                       self);
-  cc_object_storage_create_dbus_proxy (G_BUS_TYPE_SESSION,
-                                       G_DBUS_PROXY_FLAGS_NONE,
-                                       "org.gnome.SettingsDaemon.Power",
-                                       "/org/gnome/SettingsDaemon/Power",
-                                       "org.gnome.SettingsDaemon.Power.Keyboard",
-                                       cc_panel_get_cancellable (CC_PANEL (self)),
-                                       got_kbd_proxy_cb,
-                                       self);
-
   self->chassis_type = get_chassis_type (cc_panel_get_cancellable (CC_PANEL (self)));
 
   self->up_client = up_client_new ();
diff --git a/panels/power/meson.build b/panels/power/meson.build
index 737d86817..1700c91e8 100644
--- a/panels/power/meson.build
+++ b/panels/power/meson.build
@@ -17,7 +17,14 @@ i18n.merge_file(
   install_dir: control_center_desktopdir
 )
 
-sources = files('cc-power-panel.c')
+sources = files(
+  'cc-brightness-scale.c',
+  'cc-power-panel.c'
+)
+
+sources += gnome.mkenums_simple(
+  'cc-brightness-scale-types',
+  sources: ['cc-brightness-scale.h'])
 
 resource_data = files('cc-power-panel.ui')