pci, acpi: reroute PCI interrupt to legacy boot interrupt equivalent

[linux-2.6-omap-h63xx.git] / drivers / acpi / pci_irq.c

diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
index 89022a74faeeda9d9ed9b11f431c2e4c4eecb4d7..b37cb0a9826ee85699d5f5328b2815001f9063a5 100644 (file)
--- a/drivers/acpi/pci_irq.c
+++ b/drivers/acpi/pci_irq.c
@@ -384,6 +384,27 @@ acpi_pci_free_irq(struct acpi_prt_entry *entry,
        return irq;
 }
 
+#ifdef CONFIG_X86_IO_APIC
+extern int noioapicquirk;
+
+static int bridge_has_boot_interrupt_variant(struct pci_bus *bus)
+{
+       struct pci_bus *bus_it;
+
+       for (bus_it = bus ; bus_it ; bus_it = bus_it->parent) {
+               if (!bus_it->self)
+                       return 0;
+
+               printk(KERN_INFO "vendor=%04x device=%04x\n", bus_it->self->vendor,
+                               bus_it->self->device);
+
+               if (bus_it->self->irq_reroute_variant)
+                       return bus_it->self->irq_reroute_variant;
+       }
+       return 0;
+}
+#endif /* CONFIG_X86_IO_APIC */
+
 /*
  * acpi_pci_irq_lookup
  * success: return IRQ >= 0
@@ -413,6 +434,41 @@ acpi_pci_irq_lookup(struct pci_bus *bus,
        }
 
        ret = func(entry, triggering, polarity, link);
+
+#ifdef CONFIG_X86_IO_APIC
+       /*
+        * Some chipsets (e.g. intel 6700PXH) generate a legacy INTx when the
+        * IRQ entry in the chipset's IO-APIC is masked (as, e.g. the RT kernel
+        * does during interrupt handling). When this INTx generation cannot be
+        * disabled, we reroute these interrupts to their legacy equivalent to
+        * get rid of spurious interrupts.
+        */
+        if (!noioapicquirk) {
+               switch (bridge_has_boot_interrupt_variant(bus)) {
+               case 0:
+                       /* no rerouting necessary */
+                       break;
+
+               case INTEL_IRQ_REROUTE_VARIANT:
+                       /*
+                        * Remap according to INTx routing table in 6700PXH
+                        * specs, intel order number 302628-002, section
+                        * 2.15.2. Other chipsets (80332, ...) have the same
+                        * mapping and are handled here as well.
+                        */
+                       printk(KERN_INFO "pci irq %d -> rerouted to legacy "
+                                        "irq %d\n", ret, (ret % 4) + 16);
+                       ret = (ret % 4) + 16;
+                       break;
+
+               default:
+                       printk(KERN_INFO "not rerouting irq %d to legacy irq: "
+                                        "unknown mapping\n", ret);
+                       break;
+               }
+       }
+#endif /* CONFIG_X86_IO_APIC */
+
        return ret;
 }