[RFC] serio driver: speed up resume

[Shaohua Li <shaohua.li@intel.com>]

serio_resume will call into psmouse_extensions(). In my test, the
routine is very slow, it blocks resume about 1 sec. Below patch (move
resume to kseriod, just like boot time probe) cures the issue in my
test, and seems no side effect. I'm no familiar with serio driver, so
please check. 

Signed-off-by: Shaohua Li <shaohua.li@intel.com>

diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c
index 7f52938..7dad33f 100644
--- a/drivers/input/serio/serio.c
+++ b/drivers/input/serio/serio.c
@@ -163,6 +163,7 @@ enum serio_event_type {
 	SERIO_RECONNECT_PORT,
 	SERIO_REGISTER_PORT,
 	SERIO_ATTACH_DRIVER,
+	SERIO_RESUME_PORT,
 };
 
 struct serio_event {
@@ -287,6 +288,13 @@ static struct serio_event *serio_get_event(void)
 	return event;
 }
 
+#ifdef CONFIG_PM
+static void serio_resume_port(struct device *dev);
+#else
+static inline void serio_resume_port(struct device *dev)
+{
+}
+#endif /* CONFIG_PM */
 static void serio_handle_event(void)
 {
 	struct serio_event *event;
@@ -319,6 +327,10 @@ static void serio_handle_event(void)
 				serio_attach_driver(event->object);
 				break;
 
+			case SERIO_RESUME_PORT:
+				serio_resume_port(event->object);
+				break;
+
 			default:
 				break;
 		}
@@ -922,21 +934,26 @@ static int serio_suspend(struct device *dev, pm_message_t state)
 	return 0;
 }
 
-static int serio_resume(struct device *dev)
+static void serio_resume_port(struct device *dev)
 {
 	struct serio *serio = to_serio_port(dev);
 
-	if (dev->power.power_state.event != PM_EVENT_ON &&
-	    serio_reconnect_driver(serio)) {
-		/*
-		 * Driver re-probing can take a while, so better let kseriod
-		 * deal with it.
-		 */
-		serio_rescan(serio);
+	if (serio_reconnect_driver(serio)) {
+		serio_disconnect_port(serio);
+		serio_find_driver(serio);
 	}
 
 	dev->power.power_state = PMSG_ON;
+}
 
+static int serio_resume(struct device *dev)
+{
+	/*
+	 * Driver reconnect can take a while, so better let kseriod
+	 * deal with it.
+	 */
+	if (dev->power.power_state.event != PM_EVENT_ON)
+		serio_queue_event(dev, NULL, SERIO_RESUME_PORT);
 	return 0;
 }
 #endif /* CONFIG_PM */