msi-laptop: 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>
diff --git a/drivers/misc/msi-laptop.c b/drivers/misc/msi-laptop.c
index de898c6..759763d 100644
--- a/drivers/misc/msi-laptop.c
+++ b/drivers/misc/msi-laptop.c
@@ -347,12 +347,16 @@
 
 	/* Register backlight stuff */
 
-	msibl_device = backlight_device_register("msi-laptop-bl", NULL, NULL,
-						&msibl_ops);
-	if (IS_ERR(msibl_device))
-		return PTR_ERR(msibl_device);
-
-	msibl_device->props.max_brightness = MSI_LCD_LEVEL_MAX-1;
+	if (acpi_video_backlight_support()) {
+		printk(KERN_INFO "MSI: Brightness ignored, must be controlled "
+		       "by ACPI video driver\n");
+	} else {
+		msibl_device = backlight_device_register("msi-laptop-bl", NULL,
+							 NULL, &msibl_ops);
+		if (IS_ERR(msibl_device))
+			return PTR_ERR(msibl_device);
+		msibl_device->props.max_brightness = MSI_LCD_LEVEL_MAX-1;
+	}
 
 	ret = platform_driver_register(&msipf_driver);
 	if (ret)