Messages in this thread | | | Subject | Re: [PATCH v2] pci: fix unavailable irq number 255 reported by BIOS | From | Cao jin <> | Date | Wed, 27 Jan 2016 13:24:36 +0800 |
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On 01/27/2016 08:25 AM, Bjorn Helgaas wrote: > On Tue, Jan 26, 2016 at 04:48:25PM +0100, Thomas Gleixner wrote: >> On Tue, 26 Jan 2016, Bjorn Helgaas wrote:
>> >> Right. So we could certainly do something like this INVALID_IRQ thingy, but >> that looks a bit weird. What would request_irq() return? >> >> If it returns success, then drivers might make the wrong decision. If it >> returns an error code, then the i801 one works, but we might have to fix >> others anyway. > > I was thinking request_irq() could return -EINVAL if the caller passed > INVALID_IRQ. That should tell drivers that this interrupt won't work. > > We'd be making request_irq() return -EINVAL in some cases where it > currently returns success. But even though it returns success today, > I don't think the driver is getting interrupts, because the wire isn't > connected. > >> I think it's better to have a software flag in pci_dev to indicate that there >> is no irq line and fix up the (probably few) affected drivers so they avoid >> calling request_irq() and take the right action. > > We could add an "irq_valid" flag in struct pci_dev and make a new > rule that drivers should check dev->irq_valid before using dev->irq. > But realistically, i801 is the only place that will check irq_valid > because that's the only driver where we know about a problem, so that > seems like sort of a point solution. > > Bjorn >
How about using IRQ_BITMAP_BITS as that "irq_valid" flag? because it is the ceiling of struct irq_desc irq_desc[], and request_irq() will return -EINVAL in case of the ceiling.
#ifdef CONFIG_SPARSE_IRQ # define IRQ_BITMAP_BITS (NR_IRQS + 8196) #else # define IRQ_BITMAP_BITS NR_IRQS #endif
> . >
-- Yours Sincerely,
Cao jin
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