Re: RFC: Changes for PCI

From: Jeff Garzik (
Date: Wed Jun 27 2001 - 18:34:24 EST

Tom Gall wrote:
> Well you have device drivers like the symbios scsi driver for instance that
> tries to determine if it's seen a card before. It does this by looking at the
> bus,dev etc numbers... It's quite reasonable for two different scsi cards to be
> on the same bus number, same dev number etc yet they are in different PCI
> domains.
> Is this a device driver bug or feature?

I hesitate to call it a device driver bug, because that was likely the
best decision Gerard could make at the time.

However, I think the driver (only going by your description) would be
more correct to use a pointer to struct pci_dev. We have a token in the
kernel that is guaranteed 100% unique to any given PCI device: the
pointer to its struct pci_dev.

> > Changing the meaning of dev->bus->number globally seems pointless. If
> > you are going to do that, just do it the right way and introduce another
> > struct member, pci_domain or somesuch.
> Right, one could do that and then all the large machine architectures would have
> their own implementation for the same problem. That's not necessarily a bad
> thing, but some commonality I think would be a good thing.

Sorry, not pci_domain, just system bus number, for any bus, like we
talked about in the previous discussion.


Jeff Garzik      | Andre the Giant has a posse.
Building 1024    |
MandrakeSoft     |
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