Index: sys/amd64/pci/pci_cfgreg.c
===================================================================
--- sys/amd64/pci/pci_cfgreg.c
+++ sys/amd64/pci/pci_cfgreg.c
@@ -72,46 +72,16 @@
     "Enable support for PCI-e memory mapped config access");
 
 /* 
- * Initialise access to PCI configuration space 
+ * Initialize access to PCI configuration space.  The initialization
+ * is temporal and only used for early pci config accesses.  Later,
+ * acpi subsystem calls pcie_cfgregopen() when MCFG table is found.
  */
 int
 pci_cfgregopen(void)
 {
-	uint64_t pciebar;
-	uint16_t did, vid;
-
-	if (cfgmech != CFGMECH_NONE)
-		return (1);
-	cfgmech = CFGMECH_1;
-
-	/*
-	 * Grope around in the PCI config space to see if this is a
-	 * chipset that is capable of doing memory-mapped config cycles.
-	 * This also implies that it can do PCIe extended config cycles.
-	 */
-
-	/* Check for supported chipsets */
-	vid = pci_cfgregread(0, 0, 0, PCIR_VENDOR, 2);
-	did = pci_cfgregread(0, 0, 0, PCIR_DEVICE, 2);
-	switch (vid) {
-	case 0x8086:
-		switch (did) {
-		case 0x3590:
-		case 0x3592:
-			/* Intel 7520 or 7320 */
-			pciebar = pci_cfgregread(0, 0, 0, 0xce, 2) << 16;
-			pcie_cfgregopen(pciebar, 0, 255);
-			break;
-		case 0x2580:
-		case 0x2584:
-		case 0x2590:
-			/* Intel 915, 925, or 915GM */
-			pciebar = pci_cfgregread(0, 0, 0, 0x48, 4);
-			pcie_cfgregopen(pciebar, 0, 255);
-			break;
-		}
-	}
 
+	if (cfgmech == CFGMECH_NONE)
+		cfgmech = CFGMECH_1;
 	return (1);
 }