diff --git a/arch/x86/pci/irq.c b/arch/x86/pci/irq.c
index 373b9afe6d4445b08efee66dfb4856519b434bd1..399a172f047ddb2823e3df9dc53ef1700636a319 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 3222f9022707a3b6eed7fe15767a1247371947ae..bd52ca4c28933804dda155941c13e4c01f99095d 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;