From 5ebc76035303016ec41bb752bec156ea9fde7c34 Mon Sep 17 00:00:00 2001 From: Jiang Liu Date: Thu, 17 Sep 2015 14:02:45 +0800 Subject: ACPI, PCI, irq: Do not share PCI IRQ with ISA IRQ Avoid IRQs occupied by ISA IRQs when allocating IRQs for PCI link devices, otherwise it may cause interrupt storm due to incompatible pin attributes. This issue was triggered on a KVM virtual machine, which 1) uses IRQ9 for SCI in high level mode. 2) defines an PCI interrupt link device (LNKS) with IRQ9 as the only possible irq. 3) has an PCI device referring to link device LNKS. So it causes interrupt storm when enabling the PCI device because PCI IRQ works in low level mode. Signed-off-by: Jiang Liu Acked-by: Bjorn Helgaas Signed-off-by: Rafael J. Wysocki --- drivers/acpi/pci_irq.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/acpi/pci_irq.c') diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c index 6da0f9beab19..c9336751e5e3 100644 --- a/drivers/acpi/pci_irq.c +++ b/drivers/acpi/pci_irq.c @@ -372,6 +372,7 @@ static int acpi_isa_register_gsi(struct pci_dev *dev) /* Interrupt Line values above 0xF are forbidden */ if (dev->irq > 0 && (dev->irq <= 0xF) && + acpi_isa_irq_available(dev->irq) && (acpi_isa_irq_to_gsi(dev->irq, &dev_gsi) == 0)) { dev_warn(&dev->dev, "PCI INT %c: no GSI - using ISA IRQ %d\n", pin_name(dev->pin), dev->irq); -- cgit v1.2.3