Subject: Re: Another changer, another changer problem
To: David Maxwell <email@example.com>
From: Bill Studenmund <firstname.lastname@example.org>
Date: 10/05/1998 14:02:57
On Mon, 5 Oct 1998, David Maxwell wrote:
> > No one's mentioned it, but you can.
> > ahc1 at pci0 dev 12 function <whatever>
> > ahc2 at pci0 dev 13 function <whatever>
> I have a feeling that certain BIOS' (What the plural of BIOS? BIOSae?) may
> not keep these constant, or for that matter that different BIOS sets will
> pick the same numbers if you swap a motherboard. I also don't know how to
> find these numbers out except by booting multiple times and adding one
> card each reboot.
Actually, the "dev" number is motherboard-specific. It's a function of how
the motherboard (well, the host-PCI chipset) deals with configuration
space writes and how the board is wired. When you access a configuration
register, part of the address is decoded using a wire which is fed
directly to the chip/card.
So if you know a particular motherbaord, you can tell what card is in what
slot according to the pci device number. You probably can even get that
info from the vendor.
Though the only way I know at present to find out what's what is to do a
boot and look at the output. Though if you had three different PCI cards,
you could boot w/ each one of them in, and get all the #'s at once.