linux: Refresh devices after waking up from sleep

The battery levels might have changed drastically compared to
before sleep. Since we poll batteries at set intervals, it can
take quite some time for the new level to be picked up by the
polling code.

Listen to the "PrepareForSleep" signal emitted by logind, that
gets emitted on suspend and wake up. Pause polling globally on
suspend, and refresh all devices manually and resume polling when
waking up.

https://bugs.freedesktop.org/show_bug.cgi?id=99763

1 files changed, 74 insertions, 0 deletions

diff --git a/src/linux/up-backend.c b/src/linux/up-backend.c
index 2ba201a..edd7775 100644
--- a/src/linux/up-backend.c
+++ b/src/linux/up-backend.c
@@ -62,6 +62,7 @@ struct UpBackendPrivate
 	UpDeviceList		*managed_devices;
 	UpConfig		*config;
 	GDBusProxy		*logind_proxy;
+	guint                    logind_sleep_id;
 };
 
 enum {
@@ -460,6 +461,57 @@ up_backend_take_action (UpBackend *backend)
 }
 
 /**
+ * up_backend_prepare_for_sleep:
+ *
+ * Callback for logind's PrepareForSleep signal. It receives
+ * a boolean that indicates if we are about to sleep (TRUE)
+ * or waking up (FALSE).
+ * In case of the waking up we refresh the devices so we are
+ * up to date, especially w.r.t. battery levels, since they
+ * might have changed drastically.
+ **/
+static void
+up_backend_prepare_for_sleep (GDBusConnection *connection,
+			      const gchar     *sender_name,
+			      const gchar     *object_path,
+			      const gchar     *interface_name,
+			      const gchar     *signal_name,
+			      GVariant        *parameters,
+			      gpointer         user_data)
+{
+	UpBackend *backend = user_data;
+	gboolean will_sleep;
+	GPtrArray *array;
+	guint i;
+
+	if (!g_variant_is_of_type (parameters, G_VARIANT_TYPE ("(b)"))) {
+		g_warning ("logind PrepareForSleep has unexpected parameter(s)");
+		return;
+	}
+
+	g_variant_get (parameters, "(b)", &will_sleep);
+
+	if (will_sleep) {
+		up_daemon_pause_poll (backend->priv->daemon);
+		return;
+	}
+
+	/* we are waking up, lets refresh all battery devices */
+	g_debug ("Woke up from sleep; about to refresh devices");
+	array = up_device_list_get_array (backend->priv->device_list);
+
+	for (i = 0; i < array->len; i++) {
+		UpDevice *device = UP_DEVICE (g_ptr_array_index (array, i));
+		up_device_refresh_internal (device);
+	}
+
+	g_ptr_array_unref (array);
+
+	up_daemon_resume_poll (backend->priv->daemon);
+}
+
+
+/**
  * up_backend_class_init:
  * @klass: The UpBackendClass
  **/
@@ -491,6 +543,9 @@ up_backend_class_init (UpBackendClass *klass)
 static void
 up_backend_init (UpBackend *backend)
 {
+	GDBusConnection *bus;
+	guint sleep_id;
+
 	backend->priv = UP_BACKEND_GET_PRIVATE (backend);
 	backend->priv->config = up_config_new ();
 	backend->priv->managed_devices = up_device_list_new ();
@@ -502,6 +557,19 @@ up_backend_init (UpBackend *backend)
 								     LOGIND_DBUS_INTERFACE,
 								     NULL,
 								     NULL);
+
+	bus = g_dbus_proxy_get_connection (backend->priv->logind_proxy);
+	sleep_id = g_dbus_connection_signal_subscribe (bus,
+						       LOGIND_DBUS_NAME,
+						       LOGIND_DBUS_INTERFACE,
+						       "PrepareForSleep",
+						       LOGIND_DBUS_PATH,
+						       NULL,
+						       G_DBUS_SIGNAL_FLAGS_NONE,
+						       up_backend_prepare_for_sleep,
+						       backend,
+						       NULL);
+	backend->priv->logind_sleep_id = sleep_id;
 }
 
 /**
@@ -511,6 +579,7 @@ static void
 up_backend_finalize (GObject *object)
 {
 	UpBackend *backend;
+	GDBusConnection *bus;
 
 	g_return_if_fail (UP_IS_BACKEND (object));
 
@@ -523,6 +592,11 @@ up_backend_finalize (GObject *object)
 		g_object_unref (backend->priv->device_list);
 	if (backend->priv->gudev_client != NULL)
 		g_object_unref (backend->priv->gudev_client);
+
+	bus = g_dbus_proxy_get_connection (backend->priv->logind_proxy);
+	g_dbus_connection_signal_unsubscribe (bus,
+					      backend->priv->logind_sleep_id);
+
 	g_clear_object (&backend->priv->logind_proxy);
 
 	g_object_unref (backend->priv->managed_devices);