Messages in this thread | | | Date | Tue, 19 Feb 2013 11:40:59 -0800 | Subject | Re: [PATCH] pci: do not try to assign irq 255 | From | Yinghai Lu <> |
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On Mon, Feb 18, 2013 at 2:09 AM, Hannes Reinecke <hare@suse.de> wrote: > The PCI config space reseves a byte for the interrupt line, > so irq 255 actually refers to 'not set'. > However, the 'irq' field for struct pci_dev is an integer, > so the original meaning is lost, causing the system to > assign an interrupt '255', which fails. > > So we should _not_ assign an interrupt value here, and > allow upper layers to fixup things. > > This patch make PCI devices with MSI interrupts only > (like the xhci device on certain HP laptops) work properly.
looks like the bios does not provide _PRT for device in ACPI.
also according to PCI spec, BIOS *must* set interrupt line.
> > Cc: Frederik Himpe <fhimpe@vub.ac.be> > Cc: Oliver Neukum <oneukum@suse.de> > Cc: David Haerdeman <david@hardeman.nu> > Cc: linux-usb@vger.kernel.org > Cc: linux-pci@vger.kernel.org > Signed-off-by: Hannes Reinecke <hare@suse.de> > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 6186f03..a2db887f 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -923,7 +923,8 @@ static void pci_read_irq(struct pci_dev *dev) > dev->pin = irq; > if (irq) > pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &irq); > - dev->irq = irq; > + if (irq < 255) > + dev->irq = irq; > } > > void set_pcie_port_type(struct pci_dev *pdev) > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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