ACPI: dock: add uevent to indicate change in device status

Send a uevent to indicate a device change whenever we dock or
undock, so that userspace may now check the dock status via sysfs.

Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Holger Macht <hmacht@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/dock.c b/drivers/acpi/dock.c
index 8c6828b..215f5b3 100644
--- a/drivers/acpi/dock.c
+++ b/drivers/acpi/dock.c
@@ -326,10 +326,12 @@
 
 static void dock_event(struct dock_station *ds, u32 event, int num)
 {
+	struct device *dev = &dock_device.dev;
 	/*
-	 * we don't do events until someone tells me that
-	 * they would like to have them.
+	 * Indicate that the status of the dock station has
+	 * changed.
 	 */
+	kobject_uevent(&dev->kobj, KOBJ_CHANGE);
 }
 
 /**