--- /dev/null
+From: Stefan Assmann <sassmann@suse.de>
+Subject: pci, acpi: reroute PCI interrupt to legacy boot interrupt equivalent
+
+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). On chipsets where this INTx generation
+cannot be disabled, we reroute the valid interrupts to their legacy
+equivalent to get rid of spurious interrupts that might otherwise bring
+down (vital) interrupt lines through spurious interrupt detection in
+note_interrupt().
+
+This patch benefited from discussions with Alexander Graf, Torsten Duwe,
+Ihno Krumreich, Daniel Gollub, Hannes Reinecke. The conclusions we drew
+and the patch itself are the authors' responsibility alone.
+
+Signed-off-by: Stefan Assmann <sassmann@suse.de>
+Signed-off-by: Olaf Dabrunz <od@suse.de>
+Signed-off-by: Ingo Molnar <mingo@elte.hu>
+---
+ drivers/acpi/pci_irq.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++
+ drivers/pci/quirks.c | 26 ++++++++++++++++++++++
+ include/linux/pci.h | 6 +++++
+ 3 files changed, 88 insertions(+)
+
+--- a/drivers/acpi/pci_irq.c
++++ b/drivers/acpi/pci_irq.c
+@@ -384,6 +384,27 @@ acpi_pci_free_irq(struct acpi_prt_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;
+ }
+
+--- a/drivers/pci/quirks.c
++++ b/drivers/pci/quirks.c
+@@ -1425,6 +1425,32 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_IN
+
+ #ifdef CONFIG_X86_IO_APIC
+ /*
++ * Boot interrupts on some chipsets cannot be turned off. For these chipsets,
++ * remap the original interrupt in the linux kernel to the boot interrupt, so
++ * that a PCI device's interrupt handler is installed on the boot interrupt
++ * line instead.
++ */
++static void quirk_reroute_to_boot_interrupts_intel(struct pci_dev *dev)
++{
++ if (noioapicquirk)
++ return;
++
++ dev->irq_reroute_variant = INTEL_IRQ_REROUTE_VARIANT;
++
++ printk(KERN_INFO "PCI quirk: reroute interrupts for 0x%04x:0x%04x\n",
++ dev->vendor, dev->device);
++ return;
++}
++DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_80333_0, quirk_reroute_to_boot_interrupts_intel);
++DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_80333_1, quirk_reroute_to_boot_interrupts_intel);
++DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_ESB2_0, quirk_reroute_to_boot_interrupts_intel);
++DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_PXH_0, quirk_reroute_to_boot_interrupts_intel);
++DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_PXH_1, quirk_reroute_to_boot_interrupts_intel);
++DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_PXHV, quirk_reroute_to_boot_interrupts_intel);
++DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_80332_0, quirk_reroute_to_boot_interrupts_intel);
++DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_80332_1, quirk_reroute_to_boot_interrupts_intel);
++
++/*
+ * On some chipsets we can disable the generation of legacy INTx boot
+ * interrupts.
+ */
+--- a/include/linux/pci.h
++++ b/include/linux/pci.h
+@@ -133,6 +133,11 @@ enum pci_dev_flags {
+ PCI_DEV_FLAGS_NO_D3 = (__force pci_dev_flags_t) 2,
+ };
+
++enum pci_irq_reroute_variant {
++ INTEL_IRQ_REROUTE_VARIANT = 1,
++ MAX_IRQ_REROUTE_VARIANTS = 3
++};
++
+ typedef unsigned short __bitwise pci_bus_flags_t;
+ enum pci_bus_flags {
+ PCI_BUS_FLAGS_NO_MSI = (__force pci_bus_flags_t) 1,
+@@ -217,6 +222,7 @@ struct pci_dev {
+ unsigned int no_msi:1; /* device may not use msi */
+ unsigned int block_ucfg_access:1; /* userspace config space access is blocked */
+ unsigned int broken_parity_status:1; /* Device generates false positive parity */
++ unsigned int irq_reroute_variant:2; /* device needs IRQ rerouting variant */
+ unsigned int msi_enabled:1;
+ unsigned int msix_enabled:1;
+ unsigned int is_managed:1;
projects / people / pmueller / ipfire-2.x.git / blobdiff