Re: PCI: cardbus bridge

[Stefan Hajnoczi <stefanha@xxxxxxxxx>]

On Thu, May 24, 2012 at 9:56 AM, Zhi Yong Wu <zwu.kernel@xxxxxxxxx> wrote:
> On Thu, May 24, 2012 at 4:37 PM, Stefan Hajnoczi <stefanha@xxxxxxxxx> wrote:
>> On Thu, May 24, 2012 at 9:26 AM, Zhi Yong Wu <zwu.kernel@xxxxxxxxx> wrote:
>>> Does anyone let me know what cardbus bridge is used for? What is the
>>> difference between it and comon pci bridge?
>>
>> CardBus is PCMCIA (PC Card):
>>
>> http://en.wikipedia.org/wiki/PC_Card#CardBus
>>
>> It's not used very much anymore.  There is PCI <-> PCMCIA integration
>> and that's why you see it come up in PCI code.
> got it. thanks.
>>
>>> By the way, someone usually mentioned pci host bridge, pci root
>>> bridge. What the differences among them are?
>>
>> I'm not sure what the exact difference is.  PCI "root" bridge refers
>> to the hierarchical nature of PCI, while PCI "host" bridge refers to
> You mean that PCI "root" bridge is one alias of another some bridge?

The root bridge is the root of a tree of PCI busses.  It's the bus
that the host interacts with - there may be PCI bridges that attach
additional busses.

BTW I don't know the terminology, maybe it's PCI "domains" not
"busses".  Again, you'd have to look at the PCI specification to get
the exact definition.

>> connecting the computer to the PCI bus.
> I guess that PCI "host" bridge is the one which connects PCI bus 0 to
> host bus, and it should be contained in PMC chipset (PCI Bridge and
> Memory Controller)

Yes.

Stefan
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