diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 6a0a82f..9392ff3 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -398,6 +398,16 @@
 	pci_write_config_word(dev, rpcap + PCI_EXP_RTCTL, rpctl);
 }
 
+static void __devinit pci_fixup_parent_subordinate_busnr(struct pci_bus *child, int max)
+{
+	struct pci_bus *parent = child->parent;
+	while (parent->parent && parent->subordinate < max) {
+		parent->subordinate = max;
+		pci_write_config_byte(parent->self, PCI_SUBORDINATE_BUS, max);
+		parent = parent->parent;
+	}
+}
+
 unsigned int __devinit pci_scan_child_bus(struct pci_bus *bus);
 
 /*
@@ -499,7 +509,13 @@
 
 		if (!is_cardbus) {
 			child->bridge_ctl = PCI_BRIDGE_CTL_NO_ISA;
-
+			/*
+			 * Adjust subordinate busnr in parent buses.
+			 * We do this before scanning for children because
+			 * some devices may not be detected if the bios
+			 * was lazy.
+			 */
+			pci_fixup_parent_subordinate_busnr(child, max);
 			/* Now we can scan all subordinate buses... */
 			max = pci_scan_child_bus(child);
 		} else {
@@ -513,6 +529,7 @@
 							max+i+1))
 					break;
 			max += i;
+			pci_fixup_parent_subordinate_busnr(child, max);
 		}
 		/*
 		 * Set the subordinate bus number to its real value.