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 <alex.williamson@xxxxxxxxxx>
---
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 b1def41..4db10b1 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 ||
--
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