Re: One chart on pci bridge and its bus and their children

[Richard Yang <weiyang@linux.vnet.ibm.com>]

On Mon, Jun 04, 2012 at 10:18:46PM -0700, Yinghai Lu wrote:
>On Mon, Jun 4, 2012 at 9:37 PM, Bjorn Helgaas <bhelgaas@google.com> wrote:
>> That's true, but I don't think it answers the question.  If we have:
>>
>>    pci_bus->bridge == pci_bus->self->dev
>>
>> why would we need both "self" and "bridge"?  It would be interesting
>> to try to remove "bridge" and replace uses of it with "self->dev".
>
>then how about root bus?
>
>root bus ->self should be NULL.
>
>root bus ->bridge is to the hostbridge->dev.
>
>Yinghai

Agree, root_pci_bus->self is NULL, and root_pci_bus->bridge point to a
solo device structure, not in hostbridge. 

BTW, if the dev is the hostbrige->dev, why not pci_host_bridge contain a
field "dev"?

And, why root bus differs with other bus a lot?
Both root bus and other bus use self/bridge point to the "PCI BRIDGE"
device.
I think we can determine whether this is a root bus by bus->parent?

-- 
Richard Yang
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