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PCI/IOV: Skip INTx config reads for VFs

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Per PCIe r4.0, sec 9.2.1.4, VFs can not implement INTX, and their Interrupt
Line and Interrupt Pin registers must be RO Zero.  Some devices have
thousands of VFs, so skip reading the registers as an optimization.

Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
[bhelgaas: changelog, comment]
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
This commit is contained in:
KarimAllah Ahmed 2018-01-17 19:30:29 +01:00 committed by Bjorn Helgaas
parent 6b2f1351af
commit be20f6b063
1 changed files with 7 additions and 0 deletions
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7
drivers/pci/probe.c
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@ -1230,6 +1230,13 @@ static void pci_read_irq(struct pci_dev *dev)
{
unsigned char irq;
/* VFs are not allowed to use INTx, so skip the config reads */
if (dev->is_virtfn) {
dev->pin = 0;
dev->irq = 0;
return;
}
pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &irq);
dev->pin = irq;
if (irq)