On Sat, Apr 28, 2012 at 01:01:27PM +0800, Richard Yang wrote: >On Fri, Apr 27, 2012 at 08:17:48AM -0600, Bjorn Helgaas wrote: >>On Fri, Apr 27, 2012 at 3:27 AM, Richard Yang >><weiyang@xxxxxxxxxxxxxxxxxx> wrote: >> >>I assume your question relates to the Stratus ftServer topology. If >>so, the lspci details might clarify things. >> >Yes, my picture is a little bit related to your previous mail. >While my intention is to find out how the physical world is represented >in the kernel. > >Below is a typical topology in PCIe spec r3.0. > > +------------------+ > | | > | RC | > | Bus#0 | > | ------------- | > | | > +-+-----+--------+-+ > 00:0.0 | | | 00:02.0 > +---------+---------+ | | | +------------+-------------+ > | +------+ | +-------| PCIe 2 PCI Bridge | > | PCIe Endpoint | | | | > +-------------------+ | | Bus#2 | > | | -------------- | > | +-------+---------------+--+ > | | | > | 00:01.0 |02:00.0 |02:01.0 > +------------+-------------+ +-------+------+ +---+-------+ > | | |PCI dev | |PCI dev | > | Switch | | | | | > | Bus#1 | | | | | > | --------------- | +--------------+ +-----------+ > | | > +------------------------+-+ > | | > | | > | 01:00.0 | 01:01.0 > +---------+-------+ +--------+----------------+ > | | | | > | PCI Endpoint | | PCIe Endpoint | > | | | | > | | | | > +-----------------+ +-------------------------+ > >Do you think the current assignment of bus number and pci_dev is >correct? > BTW, if the chart is correct, 01:00.0 reprents Switch DownStream Port or the PCI Endpoint? > >>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. >> >>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 >Help you, Help me -- Richard Yang Help you, Help me -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
