From 917bfd93d3c9c644743940deaf8fe0cff77947eb Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Tue, 26 May 2015 15:11:51 -0600 Subject: [PATCH] ACPI / PCI: Account for ARI in _PRT lookups The PCIe specification, rev 3.0, section 2.2.8.1, contains the following implementation note: Virtual Wire Mapping for INTx Interrupts From ARI Devices The implied Device Number for an ARI Device is 0. When ARI-aware software (including BIOS and operating system) enables ARI Forwarding in the Downstream Port immediately above an ARI Device in order to access its Extended Functions, software must comprehend that the Downstream Port will use Device Number 0 for the virtual wire mappings of INTx interrupts coming from all Functions of the ARI Device. If non-ARI-aware software attempts to determine the virtual wire mappings for Extended Functions, it can come up with incorrect mappings by examining the traditional Device Number field and finding it to be non-0. We account for this in pci_swizzle_interrupt_pin(), but it looks like we miss it here, looking for a _PRT entry with a slot matching the ARI device slot number. This can cause errors like: pcieport 0000:80:03.0: can't derive routing for PCI INT B sfc 0000:82:01.1: PCI INT B: no GSI pci_dev.irq is then invalid, resulting in errors for drivers that attempt to enable INTx on the device. Fix by using slot 0 for ARI enabled devices. Signed-off-by: Alex Williamson Signed-off-by: Bjorn Helgaas Reviewed-by: Don Dutile Acked-by: Rafael J. Wysocki --- drivers/acpi/pci_irq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c index b1def411c0b8..4db10b189104 100644 --- a/drivers/acpi/pci_irq.c +++ b/drivers/acpi/pci_irq.c @@ -163,7 +163,7 @@ static int acpi_pci_irq_check_entry(acpi_handle handle, struct pci_dev *dev, { int segment = pci_domain_nr(dev->bus); int bus = dev->bus->number; - int device = PCI_SLOT(dev->devfn); + int device = pci_ari_enabled(dev->bus) ? 0 : PCI_SLOT(dev->devfn); struct acpi_prt_entry *entry; if (((prt->address >> 16) & 0xffff) != device || -- 2.20.1