diff --git a/arch/i386/pci/acpi.c b/arch/i386/pci/acpi.c
index b33aea8..bc8a44b 100644
--- a/arch/i386/pci/acpi.c
+++ b/arch/i386/pci/acpi.c
@@ -8,20 +8,42 @@
 struct pci_bus * __devinit pci_acpi_scan_root(struct acpi_device *device, int domain, int busnum)
 {
 	struct pci_bus *bus;
+	struct pci_sysdata *sd;
+	int pxm;
 
-	if (domain != 0) {
-		printk(KERN_WARNING "PCI: Multiple domains not supported\n");
+	/* Allocate per-root-bus (not per bus) arch-specific data.
+	 * TODO: leak; this memory is never freed.
+	 * It's arguable whether it's worth the trouble to care.
+	 */
+	sd = kzalloc(sizeof(*sd), GFP_KERNEL);
+	if (!sd) {
+		printk(KERN_ERR "PCI: OOM, not probing PCI bus %02x\n", busnum);
 		return NULL;
 	}
 
-	bus = pcibios_scan_root(busnum);
+	if (domain != 0) {
+		printk(KERN_WARNING "PCI: Multiple domains not supported\n");
+		kfree(sd);
+		return NULL;
+	}
+
+	sd->node = -1;
+
+	pxm = acpi_get_pxm(device->handle);
+#ifdef CONFIG_ACPI_NUMA
+	if (pxm >= 0)
+		sd->node = pxm_to_node(pxm);
+#endif
+
+	bus = pci_scan_bus_parented(NULL, busnum, &pci_root_ops, sd);
+	if (!bus)
+		kfree(sd);
+
 #ifdef CONFIG_ACPI_NUMA
 	if (bus != NULL) {
-		int pxm = acpi_get_pxm(device->handle);
 		if (pxm >= 0) {
-			bus->sysdata = (void *)(unsigned long)pxm_to_node(pxm);
-			printk("bus %d -> pxm %d -> node %ld\n",
-				busnum, pxm, (long)(bus->sysdata));
+			printk("bus %d -> pxm %d -> node %d\n",
+				busnum, pxm, sd->node);
 		}
 	}
 #endif
diff --git a/arch/i386/pci/common.c b/arch/i386/pci/common.c
index 3f78d4d..85503dee 100644
--- a/arch/i386/pci/common.c
+++ b/arch/i386/pci/common.c
@@ -293,6 +293,7 @@
 struct pci_bus * __devinit pcibios_scan_root(int busnum)
 {
 	struct pci_bus *bus = NULL;
+	struct pci_sysdata *sd;
 
 	dmi_check_system(pciprobe_dmi_table);
 
@@ -303,9 +304,19 @@
 		}
 	}
 
+	/* Allocate per-root-bus (not per bus) arch-specific data.
+	 * TODO: leak; this memory is never freed.
+	 * It's arguable whether it's worth the trouble to care.
+	 */
+	sd = kzalloc(sizeof(*sd), GFP_KERNEL);
+	if (!sd) {
+		printk(KERN_ERR "PCI: OOM, not probing PCI bus %02x\n", busnum);
+		return NULL;
+	}
+
 	printk(KERN_DEBUG "PCI: Probing PCI hardware (bus %02x)\n", busnum);
 
-	return pci_scan_bus_parented(NULL, busnum, &pci_root_ops, NULL);
+	return pci_scan_bus_parented(NULL, busnum, &pci_root_ops, sd);
 }
 
 extern u8 pci_cache_line_size;