ACPI: dock: avoid check _STA method

In some BIOSes, every _STA method call will send a notification again,
this cause freeze. And in some BIOSes, it appears _STA should be called
after _DCK. This tries to avoid calls _STA, and still keep the device
present check.

http://bugzilla.kernel.org/show_bug.cgi?id=10431

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/dock.c

@@ -604,14 +604,17 @@ static int handle_eject_request(struct dock_station *ds, u32 event)
 static void dock_notify(acpi_handle handle, u32 event, void *data)
 {
 	struct dock_station *ds = data;
+	struct acpi_device *tmp;
 
 	switch (event) {
 	case ACPI_NOTIFY_BUS_CHECK:
-		if (!dock_in_progress(ds) && dock_present(ds)) {
+		if (!dock_in_progress(ds) && acpi_bus_get_device(ds->handle,
+		   &tmp)) {
 			begin_dock(ds);
 			dock(ds);
 			if (!dock_present(ds)) {
 				printk(KERN_ERR PREFIX "Unable to dock!\n");
+				complete_dock(ds);
 				break;
 			}
 			atomic_notifier_call_chain(&dock_notifier_list,