diff --git a/src/linux/up-device-supply.c b/src/linux/up-device-supply.c
index d2d2e24..9341cb0 100644
--- a/src/linux/up-device-supply.c
+++ b/src/linux/up-device-supply.c
@@ -47,6 +47,12 @@
 /* number of old energy values to keep cached */
 #define UP_DEVICE_SUPPLY_ENERGY_OLD_LENGTH		4
 
+typedef enum {
+	REFRESH_RESULT_FAILURE = 0,
+	REFRESH_RESULT_SUCCESS = 1,
+	REFRESH_RESULT_NO_DATA
+} RefreshResult;
+
 struct UpDeviceSupplyPrivate
 {
 	guint			 poll_timer_id;
@@ -67,12 +73,7 @@ G_DEFINE_TYPE (UpDeviceSupply, up_device_supply, UP_TYPE_DEVICE)
 
 static gboolean		 up_device_supply_refresh	 	(UpDevice *device);
 
-/**
- * up_device_supply_refresh_line_power:
- *
- * Return %TRUE on success, %FALSE if we failed to refresh or no data
- **/
-static gboolean
+static RefreshResult
 up_device_supply_refresh_line_power (UpDeviceSupply *supply)
 {
 	UpDevice *device = UP_DEVICE (supply);
@@ -89,7 +90,7 @@ up_device_supply_refresh_line_power (UpDeviceSupply *supply)
 	native_path = g_udev_device_get_sysfs_path (native);
 	g_object_set (device, "online", sysfs_get_int (native_path, "online"), NULL);
 
-	return TRUE;
+	return REFRESH_RESULT_SUCCESS;
 }
 
 /**
@@ -516,17 +517,11 @@ sysfs_get_capacity_level (const char    *native_path,
 	return ret;
 }
 
-/**
- * up_device_supply_refresh_battery:
- *
- * Return %TRUE on success, %FALSE if we failed to refresh or no data
- **/
-static gboolean
+static RefreshResult
 up_device_supply_refresh_battery (UpDeviceSupply *supply,
 				  UpDeviceState  *out_state)
 {
 	gchar *technology_native = NULL;
-	gboolean ret = TRUE;
 	gdouble voltage_design;
 	UpDeviceState old_state;
 	UpDeviceState state;
@@ -845,7 +840,7 @@ out:
 	g_free (manufacturer);
 	g_free (model_name);
 	g_free (serial_number);
-	return ret;
+	return REFRESH_RESULT_SUCCESS;
 }
 
 static GUdevDevice *
@@ -893,16 +888,10 @@ up_device_supply_get_sibling_with_subsystem (GUdevDevice *device,
 	return sibling;
 }
 
-/**
- * up_device_supply_refresh_device:
- *
- * Return %TRUE on success, %FALSE if we failed to refresh or no data
- **/
-static gboolean
+static RefreshResult
 up_device_supply_refresh_device (UpDeviceSupply *supply,
 				 UpDeviceState  *out_state)
 {
-	gboolean ret = TRUE;
 	UpDeviceState state;
 	UpDevice *device = UP_DEVICE (supply);
 	const gchar *native_path;
@@ -966,7 +955,7 @@ up_device_supply_refresh_device (UpDeviceSupply *supply,
 		state = UP_DEVICE_STATE_UNKNOWN;
 		g_object_set (device, "state", state, NULL);
 		*out_state = state;
-		return FALSE;
+		return REFRESH_RESULT_NO_DATA;
 	}
 
 	state = up_device_supply_get_state (native_path);
@@ -990,7 +979,7 @@ up_device_supply_refresh_device (UpDeviceSupply *supply,
 
 	*out_state = state;
 
-	return ret;
+	return REFRESH_RESULT_SUCCESS;
 }
 
 static gboolean
@@ -1073,6 +1062,7 @@ up_device_supply_coldplug (UpDevice *device)
 	const gchar *native_path;
 	const gchar *scope;
 	UpDeviceKind type;
+	RefreshResult ret;
 
 	up_device_supply_reset_values (supply);
 
@@ -1127,7 +1117,8 @@ up_device_supply_coldplug (UpDevice *device)
 		up_daemon_start_poll (G_OBJECT (device), (GSourceFunc) up_device_supply_refresh);
 
 	/* coldplug values */
-	return up_device_supply_refresh (device);
+	ret = up_device_supply_refresh (device);
+	return (ret != REFRESH_RESULT_FAILURE);
 }
 
 /**
@@ -1166,15 +1157,10 @@ up_device_supply_disable_unknown_poll (UpDevice *device)
 	}
 }
 
-/**
- * up_device_supply_refresh:
- *
- * Return %TRUE on success, %FALSE if we failed to refresh or no data
- **/
 static gboolean
 up_device_supply_refresh (UpDevice *device)
 {
-	gboolean ret;
+	RefreshResult ret;
 	UpDeviceSupply *supply = UP_DEVICE_SUPPLY (device);
 	UpDeviceKind type;
 	UpDeviceState state;
@@ -1195,10 +1181,10 @@ up_device_supply_refresh (UpDevice *device)
 	}
 
 	/* reset time if we got new data */
-	if (ret)
+	if (ret == REFRESH_RESULT_SUCCESS)
 		g_object_set (device, "update-time", (guint64) g_get_real_time () / G_USEC_PER_SEC, NULL);
 
-	return ret;
+	return (ret != REFRESH_RESULT_FAILURE);
 }
 
 /**