1 files changed, 18 insertions, 1 deletions

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 6a0a82f0508b..9392ff3fb803 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -398,6 +398,16 @@ static void pci_enable_crs(struct pci_dev *dev)
         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 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max
 
                 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 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max
                                                         max+i+1))
                                         break;
                         max += i;
+                        pci_fixup_parent_subordinate_busnr(child, max);
                 }
                 /*
                  * Set the subordinate bus number to its real value.