2 files changed, 3 insertions, 3 deletions

diff --git a/arch/x86/pci/irq.c b/arch/x86/pci/irq.c
index 373b9afe6d44..399a172f047d 100644
--- a/arch/x86/pci/irq.c
+++ b/arch/x86/pci/irq.c
@@ -533,7 +533,7 @@ static int pirq_bios_set(struct pci_dev *router, struct pci_dev *dev, int pirq,
 {
         struct pci_dev *bridge;
         int pin = pci_get_interrupt_pin(dev, &bridge);
-        return pcibios_set_irq_routing(bridge, pin, irq);
+        return pcibios_set_irq_routing(bridge, pin - 1, irq);
 }
 
 #endif
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 3222f9022707..bd52ca4c2893 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1374,9 +1374,9 @@ pci_get_interrupt_pin(struct pci_dev *dev, struct pci_dev **bridge)
         pin = dev->pin;
         if (!pin)
                 return -1;
-        pin--;
+
         while (dev->bus->self) {
-                pin = (pin + PCI_SLOT(dev->devfn)) % 4;
+                pin = (((pin - 1) + PCI_SLOT(dev->devfn)) % 4) + 1;
                 dev = dev->bus->self;
         }
         *bridge = dev;