1 files changed, 7 insertions, 4 deletions

diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
index e42481f64495..b35e64d71409 100644
--- a/drivers/acpi/pci_irq.c
+++ b/drivers/acpi/pci_irq.c
@@ -399,7 +399,7 @@ static struct acpi_prt_entry *
 acpi_pci_irq_derive(struct pci_dev *dev, int pin)
 {
         struct acpi_prt_entry *entry = NULL;
-        struct pci_dev *bridge = dev;
+        struct pci_dev *bridge;
         u8 bridge_pin = 0, orig_pin = pin;
 
 
@@ -407,9 +407,9 @@ acpi_pci_irq_derive(struct pci_dev *dev, int pin)
          * Attempt to derive an IRQ for this device from a parent bridge's
          * PCI interrupt routing entry (eg. yenta bridge and add-in card bridge).
          */
-        while (bridge->bus->self) {
-                pin = (((pin - 1) + PCI_SLOT(bridge->devfn)) % 4) + 1;
-                bridge = bridge->bus->self;
+        bridge = dev->bus->self;
+        while (bridge) {
+                pin = (((pin - 1) + PCI_SLOT(dev->devfn)) % 4) + 1;
 
                 if ((bridge->class >> 8) == PCI_CLASS_BRIDGE_CARDBUS) {
                         /* PC card has the same IRQ as its cardbridge */
@@ -431,6 +431,9 @@ acpi_pci_irq_derive(struct pci_dev *dev, int pin)
                                          pci_name(bridge)));
                         return entry;
                 }
+
+                dev = bridge;
+                bridge = dev->bus->self;
         }
 
         dev_warn(&dev->dev, "can't derive routing for PCI INT %c\n",