Re: /proc/pci deprecation?

From: Vojtech Pavlik (
Date: Mon Dec 09 2002 - 18:27:29 EST

On Mon, Dec 09, 2002 at 09:00:44AM -0800, Linus Torvalds wrote:

> On 9 Dec 2002, Alan Cox wrote:
> >
> > I wonder if this is why we have all these problems with VIA chipset
> > interrupt handling. According to VIA docs they _do_ use
> > PCI_INTERRUPT_LINE on integrated devices to select the IRQ routing
> > between APIC and PCI/ISA etc, as well as 0 meaning "IRQ disabled"
> Whee.. That sounds like a load of crock in the first place, since the
> PCI_INTERRUPT_LINE thing should be just a scratch register as far as I
> know. However, it doesn't really matter - we definitely should never write
> to it anyway, so the VIA behaviour while strange should still be
> acceptable.

I can confirm that on most builtin VIA southbridge devices (namely USB)
the register isn't just a scratch register and that indeed it is used by
the interrupt router.

> Anyway, to get back on the original discussion, I think we should remove
> the writing, and then make sure that /sbin/lspci (or some other tool) can

I guess only the irq re-routing code specific to VIA would then write
those values, because it has to if the BIOS didn't set them up correctly.

> be made to easily show either the kernel irq mapping value _or_ the
> "original PCI config space" value. At that point I'd agree that /proc/pci
> has outlived its usefulness.
> (Although I still think the name database is nice to have - I certainly
> prefer it over having a lot of drivers having their _own_ name databases
> for printout purposes).

It definitely made many drivers simpler.

Vojtech Pavlik
SuSE Labs
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