Messages in this thread | | | Date | Thu, 28 Jun 2001 17:12:15 -0400 | From | Jeff Garzik <> | Subject | Re: RFC: Changes for PCI |
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Gérard Roudier wrote: > The driver checks against PCI bus+dev+func in 2 situations: > > 1) To apply the boot order that user can set up in the controller NVRAMs. > 2) To detect buggy double reporting of the same device by the kernel PCI > code (this made lot of troubles at some time).
Cool. The premise of the thread was that you merely were checking for uniqueness, not order. That changes our answer...
> The great bug is to invent useless abstractions that don't match reality. > Such brain masturbation leads to confusion (hence subtle bugs) and > useless software bloatage (thus _real_ resource wastage). > > If we want to handle _real_ PCI bus domains, we just have to add a domain > number to identify a _real_ PCI device. Anything that wants to hide such > reality in some opaque data looks like brain masturbation to me.
I think all of us agree on this: in 2.5, our solution is to have a system domain number, which increases from zero each time you add sbus, pci bus, isa bus, etc.
For 2.4, non-x86 arches first had to deal with PCI domains, so the solution was to stick "arch-specific data" into pci_dev->sysdata, which in some cases was the PCI domain number.
So, you have an ugly solution in drivers for 2.4 if you need to know PCI domain for what reason, and a clean solution in 2.5.
Jeff
-- Jeff Garzik | Andre the Giant has a posse. Building 1024 | MandrakeSoft | - 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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