diff --git a/drivers/acpi/ibm_acpi.c b/drivers/acpi/ibm_acpi.c
index 1397efb..da08b9c 100644
--- a/drivers/acpi/ibm_acpi.c
+++ b/drivers/acpi/ibm_acpi.c
@@ -1714,7 +1714,7 @@
 
 static int brightness_init(void)
 {
-	ibm_backlight_device = backlight_device_register("ibm", NULL,
+	ibm_backlight_device = backlight_device_register("ibm", NULL, NULL,
 							 &ibm_backlight_data);
 	if (IS_ERR(ibm_backlight_device)) {
 		printk(IBM_ERR "Could not register backlight device\n");