kms: Notify about privacy screen changes via predictions

When we change the privacy screen, we added a result listener to the KMS
update object to notify the upper layer about the privacy screen state
change. This was slightly awkward as one might have changed the state
multiple times for a single update, thus it was necessary to remove any
old result listeners to an update before adding a new one.

Doing this will not be possible when updates are fully async and managed
by the KMS impl device.

To handle this, instead make the post-commit prediction notify about
changes that happens in response to a successfully committed update. We
already predicted the new privacy screen state, so the necessary change
was to plumb the actual change into a callback which emits the signal if
there actually was a privacy screen change.

This will then be communicated via the same signal listener that already
listens to the 'resources-changed' signal.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2340>

src/backends/meta-monitor-manager-private.h

@@ -246,9 +246,6 @@ struct _MetaMonitorManagerClass
                            unsigned short     *green,
                            unsigned short     *blue);
 
-  gboolean (* set_privacy_screen_enabled) (MetaMonitorManager *manager,
-                                           gboolean            enabled);
-
   void (* tiled_monitor_added) (MetaMonitorManager *manager,
                                 MetaMonitor        *monitor);
 

src/backends/meta-monitor-manager.c

@@ -1009,17 +1009,21 @@ experimental_features_changed (MetaSettings           *settings,
 }
 
 static gboolean
-meta_monitor_manager_real_set_privacy_screen_enabled (MetaMonitorManager *manager,
+ensure_privacy_screen_settings (MetaMonitorManager *manager)
-                                                      gboolean            enabled)
 {
+  MetaSettings *settings = meta_backend_get_settings (manager->backend);
+  gboolean privacy_screen_enabled;
   GList *l;
 
+  privacy_screen_enabled = meta_settings_is_privacy_screen_enabled (settings);
   for (l = manager->monitors; l; l = l->next)
     {
-      g_autoptr (GError) error = NULL;
       MetaMonitor *monitor = l->data;
+      g_autoptr (GError) error = NULL;
 
-      if (!meta_monitor_set_privacy_screen_enabled (monitor, enabled, &error))
+      if (!meta_monitor_set_privacy_screen_enabled (monitor,
+                                                    privacy_screen_enabled,
+                                                    &error))
         {
           if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED))
             continue;
@@ -1033,25 +1037,6 @@ meta_monitor_manager_real_set_privacy_screen_enabled (MetaMonitorManager *manage
   return TRUE;
 }
 
-static gboolean
-set_privacy_screen_enabled (MetaMonitorManager *manager,
-                            gboolean            enabled)
-{
-  MetaMonitorManagerClass *manager_class =
-    META_MONITOR_MANAGER_GET_CLASS (manager);
-
-  return manager_class->set_privacy_screen_enabled (manager, enabled);
-}
-
-static gboolean
-ensure_monitors_settings (MetaMonitorManager *manager)
-{
-  MetaSettings *settings = meta_backend_get_settings (manager->backend);
-
-  return set_privacy_screen_enabled (
-    manager, meta_settings_is_privacy_screen_enabled (settings));
-}
-
 static MetaPrivacyScreenState
 get_global_privacy_screen_state (MetaMonitorManager *manager)
 {
@@ -1098,7 +1083,7 @@ static void
 apply_privacy_screen_settings (MetaMonitorManager *manager)
 {
   if (privacy_screen_needs_update (manager) &&
-      ensure_monitors_settings (manager))
+      ensure_privacy_screen_settings (manager))
     {
       manager->privacy_screen_change_state =
         META_PRIVACY_SCREEN_CHANGE_STATE_PENDING_SETTING;
@@ -1396,8 +1381,6 @@ meta_monitor_manager_class_init (MetaMonitorManagerClass *klass)
 
   klass->read_edid = meta_monitor_manager_real_read_edid;
   klass->read_current_state = meta_monitor_manager_real_read_current_state;
-  klass->set_privacy_screen_enabled =
-    meta_monitor_manager_real_set_privacy_screen_enabled;
 
   signals[MONITORS_CHANGED] =
     g_signal_new ("monitors-changed",
@@ -3619,7 +3602,7 @@ meta_monitor_manager_rebuild (MetaMonitorManager *manager,
 
   meta_monitor_manager_notify_monitors_changed (manager);
 
-  ensure_monitors_settings (manager);
+  ensure_privacy_screen_settings (manager);
 
   g_list_free_full (old_logical_monitors, g_object_unref);
 }

src/backends/native/meta-kms-connector-private.h

@@ -106,8 +106,8 @@ MetaKmsResourceChanges meta_kms_connector_update_state (MetaKmsConnector *connec
 
 void meta_kms_connector_disable (MetaKmsConnector *connector);
 
-void meta_kms_connector_predict_state (MetaKmsConnector *connector,
+MetaKmsResourceChanges meta_kms_connector_predict_state (MetaKmsConnector *connector,
-                                       MetaKmsUpdate    *update);
+                                                         MetaKmsUpdate    *update);
 
 MetaKmsConnector * meta_kms_connector_new (MetaKmsImplDevice *impl_device,
                                            drmModeConnector  *drm_connector,

src/backends/native/meta-kms-connector.c

@@ -758,7 +758,7 @@ meta_kms_connector_disable (MetaKmsConnector *connector)
   current_state->current_crtc_id = 0;
 }
 
-void
+MetaKmsResourceChanges
 meta_kms_connector_predict_state (MetaKmsConnector *connector,
                                   MetaKmsUpdate    *update)
 {
@@ -766,10 +766,11 @@ meta_kms_connector_predict_state (MetaKmsConnector *connector,
   MetaKmsConnectorState *current_state;
   GList *mode_sets;
   GList *l;
+  MetaKmsResourceChanges changes = META_KMS_RESOURCE_CHANGE_NONE;
 
   current_state = connector->current_state;
   if (!current_state)
-    return;
+    return META_KMS_RESOURCE_CHANGE_NONE;
 
   mode_sets = meta_kms_update_get_mode_sets (update);
   for (l = mode_sets; l; l = l->next)
@@ -812,11 +813,19 @@ meta_kms_connector_predict_state (MetaKmsConnector *connector,
             {
               if (connector_update->privacy_screen.is_enabled)
                 {
+                  if (current_state->privacy_screen_state !=
+                      META_PRIVACY_SCREEN_ENABLED)
+                    changes |= META_KMS_RESOURCE_CHANGE_PRIVACY_SCREEN;
+
                   current_state->privacy_screen_state =
                     META_PRIVACY_SCREEN_ENABLED;
                 }
               else
                 {
+                  if (current_state->privacy_screen_state !=
+                      META_PRIVACY_SCREEN_DISABLED)
+                    changes |= META_KMS_RESOURCE_CHANGE_PRIVACY_SCREEN;
+
                   current_state->privacy_screen_state =
                     META_PRIVACY_SCREEN_DISABLED;
                 }
@@ -826,6 +835,8 @@ meta_kms_connector_predict_state (MetaKmsConnector *connector,
 
   impl_device = meta_kms_device_get_impl_device (connector->device);
   sync_fd_held (connector, impl_device);
+
+  return changes;
 }
 
 static void

src/backends/native/meta-kms-crtc-private.h

@@ -42,8 +42,8 @@ MetaKmsResourceChanges meta_kms_crtc_update_state (MetaKmsCrtc *crtc);
 
 void meta_kms_crtc_disable (MetaKmsCrtc *crtc);
 
-void meta_kms_crtc_predict_state (MetaKmsCrtc   *crtc,
+MetaKmsResourceChanges meta_kms_crtc_predict_state (MetaKmsCrtc   *crtc,
-                                  MetaKmsUpdate *update);
+                                                    MetaKmsUpdate *update);
 
 uint32_t meta_kms_crtc_get_prop_id (MetaKmsCrtc     *crtc,
                                     MetaKmsCrtcProp  prop);

src/backends/native/meta-kms-crtc.c

@@ -278,13 +278,14 @@ meta_kms_crtc_disable (MetaKmsCrtc *crtc)
   crtc->current_state.drm_mode = (drmModeModeInfo) { 0 };
 }
 
-void
+MetaKmsResourceChanges
 meta_kms_crtc_predict_state (MetaKmsCrtc   *crtc,
                              MetaKmsUpdate *update)
 {
   GList *mode_sets;
   GList *crtc_gammas;
   GList *l;
+  MetaKmsResourceChanges changes = META_KMS_RESOURCE_CHANGE_NONE;
 
   mode_sets = meta_kms_update_get_mode_sets (update);
   for (l = mode_sets; l; l = l->next)
@@ -337,8 +338,11 @@ meta_kms_crtc_predict_state (MetaKmsCrtc   *crtc,
       crtc->current_state.gamma.blue =
         g_memdup2 (gamma->blue, gamma->size * sizeof (uint16_t));
 
+      changes |= META_KMS_RESOURCE_CHANGE_GAMMA;
       break;
     }
+
+  return changes;
 }
 
 static void

src/backends/native/meta-kms-impl-device.c

@@ -914,17 +914,30 @@ err:
   return META_KMS_RESOURCE_CHANGE_FULL;
 }
 
-static void
+static MetaKmsResourceChanges
 meta_kms_impl_device_predict_states (MetaKmsImplDevice *impl_device,
                                      MetaKmsUpdate     *update)
 {
   MetaKmsImplDevicePrivate *priv =
     meta_kms_impl_device_get_instance_private (impl_device);
+  MetaKmsResourceChanges changes = META_KMS_RESOURCE_CHANGE_NONE;
+  GList *l;
 
-  g_list_foreach (priv->crtcs, (GFunc) meta_kms_crtc_predict_state,
+  for (l = priv->crtcs; l; l = l->next)
-                  update);
+    {
-  g_list_foreach (priv->connectors, (GFunc) meta_kms_connector_predict_state,
+      MetaKmsCrtc *crtc = l->data;
-                  update);
+
+      changes |= meta_kms_crtc_predict_state (crtc, update);
+    }
+
+  for (l = priv->connectors; l; l = l->next)
+    {
+      MetaKmsConnector *connector = l->data;
+
+      changes |= meta_kms_connector_predict_state (connector, update);
+    }
+
+  return changes;
 }
 
 void
@@ -944,14 +957,26 @@ meta_kms_impl_device_get_fd (MetaKmsImplDevice *impl_device)
   return meta_device_file_get_fd (priv->device_file);
 }
 
+static void
+emit_resources_changed_callback (MetaKms  *kms,
+                                 gpointer  user_data)
+{
+  MetaKmsResourceChanges changes = GPOINTER_TO_UINT (user_data);
+
+  meta_kms_emit_resources_changed (kms, changes);
+}
+
 MetaKmsFeedback *
 meta_kms_impl_device_process_update (MetaKmsImplDevice *impl_device,
                                      MetaKmsUpdate     *update,
                                      MetaKmsUpdateFlag  flags)
 {
+  MetaKmsImplDevicePrivate *priv =
+    meta_kms_impl_device_get_instance_private (impl_device);
   MetaKmsImplDeviceClass *klass = META_KMS_IMPL_DEVICE_GET_CLASS (impl_device);
   MetaKmsFeedback *feedback;
   g_autoptr (GError) error = NULL;
+  MetaKmsResourceChanges changes = META_KMS_RESOURCE_CHANGE_NONE;
 
   if (!ensure_device_file (impl_device, &error))
     return meta_kms_feedback_new_failed (NULL, g_steal_pointer (&error));
@@ -959,9 +984,17 @@ meta_kms_impl_device_process_update (MetaKmsImplDevice *impl_device,
   meta_kms_impl_device_hold_fd (impl_device);
   feedback = klass->process_update (impl_device, update, flags);
   if (!(flags & META_KMS_UPDATE_FLAG_TEST_ONLY))
-    meta_kms_impl_device_predict_states (impl_device, update);
+    changes = meta_kms_impl_device_predict_states (impl_device, update);
   meta_kms_impl_device_unhold_fd (impl_device);
 
+  if (changes != META_KMS_RESOURCE_CHANGE_NONE)
+    {
+      MetaKms *kms = meta_kms_device_get_kms (priv->device);
+
+      meta_kms_queue_callback (kms,
+                               emit_resources_changed_callback,
+                               GUINT_TO_POINTER (changes), NULL);
+    }
   return feedback;
 }
 

src/backends/native/meta-kms-private.h

@@ -61,6 +61,9 @@ gboolean meta_kms_in_impl_task (MetaKms *kms);
 
 gboolean meta_kms_is_waiting_for_impl_task (MetaKms *kms);
 
+void meta_kms_emit_resources_changed (MetaKms                *kms,
+                                      MetaKmsResourceChanges  changes);
+
 #define meta_assert_in_kms_impl(kms) \
   g_assert (meta_kms_in_impl_task (kms))
 #define meta_assert_not_in_kms_impl(kms) \

src/backends/native/meta-kms.c

@@ -651,7 +651,7 @@ handle_hotplug_event (MetaKms                *kms,
   changes |= meta_kms_update_states_sync (kms, udev_device);
 
   if (changes != META_KMS_RESOURCE_CHANGE_NONE)
-    g_signal_emit (kms, signals[RESOURCES_CHANGED], 0, changes);
+    meta_kms_emit_resources_changed (kms, changes);
 }
 
 void
@@ -799,3 +799,10 @@ meta_kms_class_init (MetaKmsClass *klass)
                   G_TYPE_NONE, 1,
                   META_TYPE_KMS_RESOURCE_CHANGES);
 }
+
+void
+meta_kms_emit_resources_changed (MetaKms                *kms,
+                                 MetaKmsResourceChanges  changes)
+{
+  g_signal_emit (kms, signals[RESOURCES_CHANGED], 0, changes);
+}

src/backends/native/meta-monitor-manager-native.c

@@ -736,69 +736,6 @@ allocate_virtual_monitor_id (MetaMonitorManagerNative *manager_native)
     }
 }
 
-static void
-on_kms_privacy_screen_update_result (const MetaKmsFeedback *kms_feedback,
-                                     gpointer               user_data)
-{
-  MetaMonitorManager *manager = user_data;
-  MetaBackend *backend = meta_monitor_manager_get_backend (manager);
-  MetaKms *kms = meta_backend_native_get_kms (META_BACKEND_NATIVE (backend));
-
-  if (meta_kms_feedback_get_result (kms_feedback) == META_KMS_FEEDBACK_FAILED)
-    {
-      manager->privacy_screen_change_state =
-        META_PRIVACY_SCREEN_CHANGE_STATE_NONE;
-      return;
-    }
-
-  on_kms_resources_changed (kms,
-                            META_KMS_RESOURCE_CHANGE_PRIVACY_SCREEN,
-                            manager);
-}
-
-static gboolean
-meta_monitor_manager_native_set_privacy_screen_enabled (MetaMonitorManager *manager,
-                                                        gboolean            enabled)
-{
-  MetaMonitorManagerClass *manager_class;
-  MetaBackend *backend = meta_monitor_manager_get_backend (manager);
-  MetaKms *kms = meta_backend_native_get_kms (META_BACKEND_NATIVE (backend));
-  gboolean any_update = FALSE;
-  GList *l;
-
-  manager_class =
-    META_MONITOR_MANAGER_CLASS (meta_monitor_manager_native_parent_class);
-
-  if (!manager_class->set_privacy_screen_enabled (manager, enabled))
-    return FALSE;
-
-  for (l = meta_kms_get_devices (kms); l; l = l->next)
-    {
-      MetaKmsDevice *kms_device = l->data;
-      MetaKmsUpdate *kms_update;
-
-      kms_update = meta_kms_get_pending_update (kms, kms_device);
-
-      if (kms_update)
-        {
-          meta_kms_update_remove_result_listeners (
-            kms_update, on_kms_privacy_screen_update_result, manager);
-          meta_kms_update_add_result_listener (
-            kms_update, on_kms_privacy_screen_update_result, manager);
-          any_update = TRUE;
-       }
-    }
-
-  if (any_update)
-    {
-      ClutterStage *stage = CLUTTER_STAGE (meta_backend_get_stage (backend));
-
-      clutter_stage_schedule_update (stage);
-    }
-
-  return TRUE;
-}
-
 static gboolean
 rebuild_virtual_idle_cb (gpointer user_data)
 {
@@ -956,8 +893,6 @@ meta_monitor_manager_native_class_init (MetaMonitorManagerNativeClass *klass)
     meta_monitor_manager_native_get_crtc_gamma;
   manager_class->set_crtc_gamma =
     meta_monitor_manager_native_set_crtc_gamma;
-  manager_class->set_privacy_screen_enabled =
-    meta_monitor_manager_native_set_privacy_screen_enabled;
   manager_class->is_transform_handled =
     meta_monitor_manager_native_is_transform_handled;
   manager_class->calculate_monitor_mode_scale =

src/backends/native/meta-output-kms.c

@@ -114,12 +114,15 @@ meta_output_kms_set_privacy_screen_enabled (MetaOutput  *output,
                                             gboolean     enabled,
                                             GError     **error)
 {
-  MetaGpu *gpu;
+  MetaGpu *gpu = meta_output_get_gpu (output);
-  MetaKms *kms;
+  MetaBackend *backend = meta_gpu_get_backend (gpu);
-  MetaKmsDevice *kms_device;
+  MetaRenderer *renderer = meta_backend_get_renderer (backend);
-  MetaKmsUpdate *kms_update;
+  MetaKmsDevice *kms_device = meta_gpu_kms_get_kms_device (META_GPU_KMS (gpu));
+  MetaKms *kms = meta_kms_device_get_kms (kms_device);
   MetaOutputKms *output_kms = META_OUTPUT_KMS (output);
   MetaKmsConnector *connector = meta_output_kms_get_kms_connector (output_kms);
+  MetaKmsUpdate *kms_update;
+  MetaCrtc *crtc;
 
   if (!meta_kms_connector_is_privacy_screen_supported (connector))
     {
@@ -128,13 +131,19 @@ meta_output_kms_set_privacy_screen_enabled (MetaOutput  *output,
       return FALSE;
     }
 
-  gpu = meta_output_get_gpu (META_OUTPUT (output_kms));
-  kms_device = meta_gpu_kms_get_kms_device (META_GPU_KMS (gpu));
-  kms = meta_kms_device_get_kms (kms_device);
   kms_update = meta_kms_ensure_pending_update (kms, kms_device);
 
   meta_kms_update_set_privacy_screen (kms_update, connector, enabled);
 
+  crtc = meta_output_get_assigned_crtc (output);
+  if (crtc)
+    {
+      MetaRendererView *view;
+
+      view = meta_renderer_get_view_for_crtc (renderer, crtc);
+      clutter_stage_view_schedule_update (CLUTTER_STAGE_VIEW (view));
+    }
+
   return TRUE;
 }