diff --git a/arch/i386/pci/mmconfig-shared.c b/arch/i386/pci/mmconfig-shared.c
index 779c987acc5b..d72f0439147c 100644
--- a/arch/i386/pci/mmconfig-shared.c
+++ b/arch/i386/pci/mmconfig-shared.c
@@ -3,6 +3,7 @@
  *                     MMCONFIG - common code between i386 and x86-64.
  *
  * This code does:
+ * - known chipset handling
  * - ACPI decoding and validation
  *
  * Per-architecture code takes care of the mappings and accesses
@@ -55,12 +56,128 @@ static __init void unreachable_devices(void)
 	}
 }
 
+static __init const char *pci_mmcfg_e7520(void)
+{
+	u32 win;
+	pci_conf1_read(0, 0, PCI_DEVFN(0,0), 0xce, 2, &win);
+
+	pci_mmcfg_config_num = 1;
+	pci_mmcfg_config = kzalloc(sizeof(pci_mmcfg_config[0]), GFP_KERNEL);
+	if (!pci_mmcfg_config)
+		return NULL;
+	pci_mmcfg_config[0].address = (win & 0xf000) << 16;
+	pci_mmcfg_config[0].pci_segment = 0;
+	pci_mmcfg_config[0].start_bus_number = 0;
+	pci_mmcfg_config[0].end_bus_number = 255;
+
+	return "Intel Corporation E7520 Memory Controller Hub";
+}
+
+static __init const char *pci_mmcfg_intel_945(void)
+{
+	u32 pciexbar, mask = 0, len = 0;
+
+	pci_mmcfg_config_num = 1;
+
+	pci_conf1_read(0, 0, PCI_DEVFN(0,0), 0x48, 4, &pciexbar);
+
+	/* Enable bit */
+	if (!(pciexbar & 1))
+		pci_mmcfg_config_num = 0;
+
+	/* Size bits */
+	switch ((pciexbar >> 1) & 3) {
+	case 0:
+		mask = 0xf0000000U;
+		len  = 0x10000000U;
+		break;
+	case 1:
+		mask = 0xf8000000U;
+		len  = 0x08000000U;
+		break;
+	case 2:
+		mask = 0xfc000000U;
+		len  = 0x04000000U;
+		break;
+	default:
+		pci_mmcfg_config_num = 0;
+	}
+
+	/* Errata #2, things break when not aligned on a 256Mb boundary */
+	/* Can only happen in 64M/128M mode */
+
+	if ((pciexbar & mask) & 0x0fffffffU)
+		pci_mmcfg_config_num = 0;
+
+	if (pci_mmcfg_config_num) {
+		pci_mmcfg_config = kzalloc(sizeof(pci_mmcfg_config[0]), GFP_KERNEL);
+		if (!pci_mmcfg_config)
+			return NULL;
+		pci_mmcfg_config[0].address = pciexbar & mask;
+		pci_mmcfg_config[0].pci_segment = 0;
+		pci_mmcfg_config[0].start_bus_number = 0;
+		pci_mmcfg_config[0].end_bus_number = (len >> 20) - 1;
+	}
+
+	return "Intel Corporation 945G/GZ/P/PL Express Memory Controller Hub";
+}
+
+struct pci_mmcfg_hostbridge_probe {
+	u32 vendor;
+	u32 device;
+	const char *(*probe)(void);
+};
+
+static __initdata struct pci_mmcfg_hostbridge_probe pci_mmcfg_probes[] = {
+	{ PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_E7520_MCH, pci_mmcfg_e7520 },
+	{ PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82945G_HB, pci_mmcfg_intel_945 },
+};
+
+static int __init pci_mmcfg_check_hostbridge(void)
+{
+	u32 l;
+	u16 vendor, device;
+	int i;
+	const char *name;
+
+	pci_conf1_read(0, 0, PCI_DEVFN(0,0), 0, 4, &l);
+	vendor = l & 0xffff;
+	device = (l >> 16) & 0xffff;
+
+	pci_mmcfg_config_num = 0;
+	pci_mmcfg_config = NULL;
+	name = NULL;
+
+	for (i = 0; !name && i < ARRAY_SIZE(pci_mmcfg_probes); i++)
+		if ((pci_mmcfg_probes[i].vendor == PCI_ANY_ID ||
+		     pci_mmcfg_probes[i].vendor == vendor) &&
+		    (pci_mmcfg_probes[i].device == PCI_ANY_ID ||
+		     pci_mmcfg_probes[i].device == device))
+			name = pci_mmcfg_probes[i].probe();
+
+	if (name) {
+		if (pci_mmcfg_config_num)
+			printk(KERN_INFO "PCI: Found %s with MMCONFIG support.\n", name);
+		else
+			printk(KERN_INFO "PCI: Found %s without MMCONFIG support.\n",
+			       name);
+	}
+
+	return name != NULL;
+}
+
 void __init pci_mmcfg_init(int type)
 {
+	int known_bridge = 0;
+
 	if ((pci_probe & PCI_PROBE_MMCONF) == 0)
 		return;
 
-	acpi_table_parse(ACPI_SIG_MCFG, acpi_parse_mcfg);
+	if (type == 1 && pci_mmcfg_check_hostbridge())
+		known_bridge = 1;
+
+	if (!known_bridge)
+		acpi_table_parse(ACPI_SIG_MCFG, acpi_parse_mcfg);
 
 	if ((pci_mmcfg_config_num == 0) ||
 	    (pci_mmcfg_config == NULL) ||
@@ -69,7 +186,7 @@ void __init pci_mmcfg_init(int type)
 
 	/* Only do this check when type 1 works. If it doesn't work
            assume we run on a Mac and always use MCFG */
-	if (type == 1 &&
+	if (type == 1 && !known_bridge &&
 	    !e820_all_mapped(pci_mmcfg_config[0].address,
 			     pci_mmcfg_config[0].address + MMCONFIG_APER_MIN,
 			     E820_RESERVED)) {