diff --git a/drivers/video/backlight/mbp_nvidia_bl.c b/drivers/video/backlight/mbp_nvidia_bl.c
index b22cfb2..dd0e145 100644
--- a/drivers/video/backlight/mbp_nvidia_bl.c
+++ b/drivers/video/backlight/mbp_nvidia_bl.c
@@ -143,6 +143,7 @@
 {
 	struct backlight_properties props;
 	struct pci_dev *host;
+	int intensity;
 
 	host = pci_get_bus_and_slot(0, 0);
 
@@ -163,6 +164,18 @@
 		return -ENODEV;
 	}
 
+	/* Check that the hardware responds - this may not work under EFI */
+
+	intensity = hw_data->backlight_ops.get_brightness(NULL);
+
+	if (!intensity) {
+		hw_data->set_brightness(1);
+		if (!hw_data->backlight_ops.get_brightness(NULL))
+			return -ENODEV;
+
+		hw_data->set_brightness(0);
+	}
+
 	if (!request_region(hw_data->iostart, hw_data->iolen,
 			    "Macbook backlight"))
 		return -ENXIO;