diff --git a/linux-core/mga_drv.c b/linux-core/mga_drv.c
index 43ba18cb..3a1e4b25 100644
--- a/linux-core/mga_drv.c
+++ b/linux-core/mga_drv.c
@@ -127,7 +127,7 @@ MODULE_LICENSE("GPL and additional rights");
  * \returns
  * If the device is a PCI G450, zero is returned.  Otherwise 2 is returned.
  */
-int mga_driver_device_is_agp(drm_device_t * dev)
+static int mga_driver_device_is_agp(drm_device_t * dev)
 {
 	const struct pci_dev * const pdev = dev->pdev;
 
@@ -141,7 +141,7 @@ int mga_driver_device_is_agp(drm_device_t * dev)
 	 * device.
 	 */
 	
-	if ( (pdev->device == 0x0525)
+	if ((pdev->device == 0x0525) && pdev->bus->self
 	     && (pdev->bus->self->vendor == 0x3388)
 	     && (pdev->bus->self->device == 0x0021) ) {
 		return 0;