asus-acpi: fingers off backlight if video.ko is serving this functionality

Signed-off-by: Thomas Renninger <trenn@suse.de>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/misc/asus-laptop.c

@@ -1208,9 +1208,13 @@ static int __init asus_laptop_init(void)
 
 	dev = acpi_get_physical_device(hotk->device->handle);
 
+	if (!acpi_video_backlight_support()) {
 		result = asus_backlight_init(dev);
 		if (result)
 			goto fail_backlight;
+	} else
+		printk(ASUS_INFO "Brightness ignored, must be controlled by "
+		       "ACPI video driver\n");
 
 	result = asus_led_init(dev);
 	if (result)