1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index aaaf0a1fed22..6f1e51d77bce 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -480,19 +480,27 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
         int is_cardbus = (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS);
         u32 buses, i, j = 0;
         u16 bctl;
+        int broken = 0;
 
         pci_read_config_dword(dev, PCI_PRIMARY_BUS, &buses);
 
         dev_dbg(&dev->dev, "scanning behind bridge, config %06x, pass %d\n",
                 buses & 0xffffff, pass);
 
+        /* Check if setup is sensible at all */
+        if (!pass &&
+            ((buses & 0xff) != bus->number || ((buses >> 8) & 0xff) <= bus->number)) {
+                dev_dbg(&dev->dev, "bus configuration invalid, reconfiguring\n");
+                broken = 1;
+        }
+
         /* Disable MasterAbortMode during probing to avoid reporting
            of bus errors (in some architectures) */ 
         pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &bctl);
         pci_write_config_word(dev, PCI_BRIDGE_CONTROL,
                               bctl & ~PCI_BRIDGE_CTL_MASTER_ABORT);
 
-        if ((buses & 0xffff00) && !pcibios_assign_all_busses() && !is_cardbus) {
+        if ((buses & 0xffff00) && !pcibios_assign_all_busses() && !is_cardbus && !broken) {
                 unsigned int cmax, busnr;
                 /*
                  * Bus already configured by firmware, process it in the first
@@ -530,7 +538,7 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,
                  * do in the second pass.
                  */
                 if (!pass) {
-                        if (pcibios_assign_all_busses())
+                        if (pcibios_assign_all_busses() || broken)
                                 /* Temporarily disable forwarding of the
                                    configuration cycles on all bridges in
                                    this bus segment to avoid possible