ACPI: video: improve PM notifer callback

PM notifier callbacks should check for supported events rather than filter
out the unsupported events. So that it won't break when a new event is
introduced.

No functional change in this patch.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/acpi_video.c

@@ -1707,24 +1707,23 @@ static int acpi_video_resume(struct notifier_block *nb,
 	int i;
 
 	switch (val) {
-	case PM_HIBERNATION_PREPARE:
-	case PM_SUSPEND_PREPARE:
-	case PM_RESTORE_PREPARE:
-		return NOTIFY_DONE;
-	}
-
-	video = container_of(nb, struct acpi_video_bus, pm_nb);
-
-	dev_info(&video->device->dev, "Restoring backlight state\n");
+	case PM_POST_HIBERNATION:
+	case PM_POST_SUSPEND:
+	case PM_POST_RESTORE:
+		video = container_of(nb, struct acpi_video_bus, pm_nb);
+
+		dev_info(&video->device->dev, "Restoring backlight state\n");
+
+		for (i = 0; i < video->attached_count; i++) {
+			video_device = video->attached_array[i].bind_info;
+			if (video_device && video_device->brightness)
+				acpi_video_device_lcd_set_level(video_device,
+						video_device->brightness->curr);
+		}
 
-	for (i = 0; i < video->attached_count; i++) {
-		video_device = video->attached_array[i].bind_info;
-		if (video_device && video_device->brightness)
-			acpi_video_device_lcd_set_level(video_device,
-					video_device->brightness->curr);
+		return NOTIFY_OK;
 	}
-
-	return NOTIFY_OK;
+	return NOTIFY_DONE;
 }
 
 static acpi_status