diff --git a/src/include/gpxe/pci.h b/src/include/gpxe/pci.h
index 9ce894b4..8bcf1e0c 100644
--- a/src/include/gpxe/pci.h
+++ b/src/include/gpxe/pci.h
@@ -43,6 +43,7 @@ FILE_LICENCE ( GPL2_ONLY );
 #define  PCI_COMMAND_WAIT 	0x80	/* Enable address/data stepping */
 #define  PCI_COMMAND_SERR	0x100	/* Enable SERR */
 #define  PCI_COMMAND_FAST_BACK	0x200	/* Enable back-to-back writes */
+#define  PCI_COMMAND_INTX_DISABLE 0x400 /* INTx Emulation Disable */
 
 
 #define PCI_VENDOR_ID           0x00    /* 16 bits */