Pull bugzilla-5637 into release branch

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
index dd3186abe07a..62010c2481b3 100644
--- a/drivers/acpi/pci_irq.c
+++ b/drivers/acpi/pci_irq.c
@@ -429,6 +429,15 @@ int acpi_pci_irq_enable(struct pci_dev *dev)
                                           &polarity, &link,
                                           acpi_pci_allocate_irq);
 
+        if (irq < 0) {
+                /*
+                 * IDE legacy mode controller IRQs are magic. Why do compat
+                 * extensions always make such a nasty mess.
+                 */
+                if (dev->class >> 8 == PCI_CLASS_STORAGE_IDE &&
+                                (dev->class & 0x05) == 0)
+                        return 0;
+        }
         /*
          * No IRQ known to the ACPI subsystem - maybe the BIOS / 
          * driver reported one, then use it. Exit in any case.