diff -uprN -x CVS -I \$FreeBSD pci/pci.c /home/john/work/p4/msi/dev/pci/pci.c
--- pci/pci.c	Sat Dec 16 09:17:12 2006
+++ /home/john/work/p4/msi/dev/pci/pci.c	Fri Dec 15 15:59:15 2006
@@ -178,11 +178,17 @@ struct pci_quirk pci_quirks[] = {
 	{ 0x02001166, PCI_QUIRK_MAP_REG,	0x90,	 0 },
 
 	/*
 	 * MSI doesn't work with the Intel E7501 chipset, at least on
 	 * the Tyan 2721 motherboard.
 	 */
 	{ 0x254c8086, PCI_QUIRK_DISABLE_MSI,	0,	0 },
 
+	/*
+	 * MSI doesn't work with devices behind the AMD 8131 HT-PCIX
+	 * bridge.
+	 */
+	{ 0x74501022, PCI_QUIRK_DISABLE_MSI,	0,	0 },
+
 	{ 0 }
 };
 
diff -uprN -x CVS -I \$FreeBSD pci/pci_pci.c /home/john/work/p4/msi/dev/pci/pci_pci.c
--- pci/pci_pci.c	Sat Dec 16 09:17:12 2006
+++ /home/john/work/p4/msi/dev/pci/pci_pci.c	Fri Dec 15 15:59:15 2006
@@ -240,6 +240,9 @@ pcib_attach_common(device_t dev)
 	}
     }
 
+    if (pci_msi_device_blacklisted(dev))
+	sc->flags |= PCIB_DISABLE_MSI;
+
     /*
      * Intel 815, 845 and other chipsets say they are PCI-PCI bridges,
      * but have a ProgIF of 0x80.  The 82801 family (AA, AB, BAM/CAM,
@@ -547,8 +550,11 @@ pcib_route_interrupt(device_t pcib, devi
 int
 pcib_alloc_msi(device_t pcib, device_t dev, int count, int maxcount, int *irqs)
 {
+	struct pcib_softc *sc = device_get_softc(dev);
 	device_t bus;
 
+	if (sc->flags & PCIB_DISABLE_MSI)
+		return (ENXIO);
 	bus = device_get_parent(pcib);
 	return (PCIB_ALLOC_MSI(device_get_parent(bus), dev, count, maxcount,
 	    irqs));
@@ -568,8 +574,11 @@ pcib_release_msi(device_t pcib, device_t
 int
 pcib_alloc_msix(device_t pcib, device_t dev, int index, int *irq)
 {
+	struct pcib_softc *sc = device_get_softc(dev);
 	device_t bus;
 
+	if (sc->flags & PCIB_DISABLE_MSI)
+		return (ENXIO);
 	bus = device_get_parent(pcib);
 	return (PCIB_ALLOC_MSIX(device_get_parent(bus), dev, index, irq));
 }
diff -uprN -x CVS -I \$FreeBSD pci/pcib_private.h /home/john/work/p4/msi/dev/pci/pcib_private.h
--- pci/pcib_private.h	Sat Dec 16 09:17:12 2006
+++ /home/john/work/p4/msi/dev/pci/pcib_private.h	Fri Dec 15 15:59:15 2006
@@ -46,6 +46,7 @@ struct pcib_softc 
     device_t	dev;
     uint32_t	flags;		/* flags */
 #define	PCIB_SUBTRACTIVE	0x1
+#define	PCIB_DISABLE_MSI	0x2
     uint16_t	command;	/* command register */
     uint8_t	secbus;		/* secondary bus number */
     uint8_t	subbus;		/* subordinate bus number */