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>

1 files changed, 28 insertions, 0 deletions

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index eb97564316d0..ac634ae2eb08 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -1365,6 +1365,34 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL,	0x260b, quirk_intel_pcie_pm);
 
 #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)
+{
+        int i;
+
+        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.
  */