Re: Does my understanding correct?

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

On Fri, Apr 27, 2012 at 08:17:48AM -0600, Bjorn Helgaas wrote:
>I assume your question relates to the Stratus ftServer topology.  If
>so, the lspci details might clarify things.
>
>In that system, my understanding is that 03:01.0 is a downstream port,
>not an upstream port.
>
>I think your picture is slightly misleading because PCIe links are not
>buses; they're point-to-point links between two devices.  You've drawn
>#3 and #5 as buses that can have several devices on them, which is not
>really the case.  The link from a downstream port should lead to
>exactly one device.
Hmm... if this is a PCI bridge, then it will have both internal bus and
externel bus? or no internal pci bus, just one external bus?
>
>That's one thing that's strange in the ftServer topology: apparently
>there are *two* devices on bus 03: the 03:00.0 upstream port and the
>03:01.0 downstream port.  I think 03:00.0 is the upstream port of a
>PCIe switch, which is perfectly normal.  My understanding is that
>03:01.0 is another *downstream* port that leads to several more
>devices (USB, NIC, etc).
>
>Bjorn

-- 
Richard Yang
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