diff --git a/sys/dev/pci/pcireg.h b/sys/dev/pci/pcireg.h
index 00589c4b83da..edec95c8e67f 100644
--- a/sys/dev/pci/pcireg.h
+++ b/sys/dev/pci/pcireg.h
@@ -122,6 +122,9 @@
 #define	PCIM_MFDEV		0x80
 #define	PCIR_BIST	0x0f
 
+/* PCI Spec rev 2.2: 0FFFFh is an invalid value for Vendor ID. */
+#define	PCIV_INVALID	0xffff 
+
 /* Capability Register Offsets */
 
 #define	PCICAP_ID	0x0