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path: root/drivers/acpi/pci_irq.c
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Diffstat (limited to 'drivers/acpi/pci_irq.c')
-rw-r--r--drivers/acpi/pci_irq.c58
1 files changed, 58 insertions, 0 deletions
diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
index f907cfbfa13c..7f9eba9a0b02 100644
--- a/drivers/acpi/pci_irq.c
+++ b/drivers/acpi/pci_irq.c
@@ -303,6 +303,61 @@ void acpi_pci_irq_del_prt(struct pci_bus *bus)
/* --------------------------------------------------------------------------
PCI Interrupt Routing Support
-------------------------------------------------------------------------- */
+#ifdef CONFIG_X86_IO_APIC
+extern int noioapicquirk;
+extern int noioapicreroute;
+
+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;
+ if (bus_it->self->irq_reroute_variant)
+ return bus_it->self->irq_reroute_variant;
+ }
+ return 0;
+}
+
+/*
+ * 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.
+ */
+static int acpi_reroute_boot_interrupt(struct pci_dev *dev,
+ struct acpi_prt_entry *entry)
+{
+ if (noioapicquirk || noioapicreroute) {
+ return 0;
+ } else {
+ switch (bridge_has_boot_interrupt_variant(dev->bus)) {
+ case 0:
+ /* no rerouting necessary */
+ return 0;
+ 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.
+ */
+ dev_info(&dev->dev, "PCI IRQ %d -> rerouted to legacy "
+ "IRQ %d\n", entry->index,
+ (entry->index % 4) + 16);
+ entry->index = (entry->index % 4) + 16;
+ return 1;
+ default:
+ dev_warn(&dev->dev, "Cannot reroute IRQ %d to legacy "
+ "IRQ: unknown mapping\n", entry->index);
+ return -1;
+ }
+ }
+}
+#endif /* CONFIG_X86_IO_APIC */
+
static struct acpi_prt_entry *acpi_pci_irq_lookup(struct pci_dev *dev, int pin)
{
struct acpi_prt_entry *entry;
@@ -311,6 +366,9 @@ static struct acpi_prt_entry *acpi_pci_irq_lookup(struct pci_dev *dev, int pin)
entry = acpi_pci_irq_find_prt_entry(dev, pin);
if (entry) {
+#ifdef CONFIG_X86_IO_APIC
+ acpi_reroute_boot_interrupt(dev, entry);
+#endif /* CONFIG_X86_IO_APIC */
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %s[%c] _PRT entry\n",
pci_name(dev), pin_name(pin)));
return entry;