Re: [patch 2/2] x86_64: Collect host bridge resources

From: Ivan Kokshaysky
Date: Tue May 24 2005 - 12:15:46 EST


On Tue, May 24, 2005 at 08:45:36AM -0700, Rajesh Shah wrote:
> The concern here isn't just increasing the size of pci_bus. The
> resource pointers in pci_bus point to resource structures in the
> corresponding pci_dev structure for p2p bridges. If we want to
> maintain this scheme, we'd have to increase the number of resources
> in the pci_dev structure too, which increases it for every single
> pci device in the system.

No. The pci_bus resource pointers are just pointers to _some_ resources
and generally aren't tied to particular pci device. For example, the
root pci buses often don't even have corresponding bus->self structure,
and bus resources are pointers to global io[mem,port]_resource.
And definitely we must not touch resource layout in struct pci_dev -
it's defined by pci specs.

> Probably ok for big server machines, but
> would others (e.g. embedded folks) complain?

Increasing the size of pci_bus by 8 or 16 bytes shouldn't be a problem -
I don't think embedded machines have a lot of pci buses. :-)
Anyway, the default PCI_BUS_NUM_RESOURCES value can be overridden in
arch specific headers.

Ivan.
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