Re: lspci: Display path to device

[Matthew Wilcox <willy@infradead.org>]

On Tue, Jul 17, 2018 at 04:00:53PM -0500, Bjorn Helgaas wrote:
> On Tue, Jul 17, 2018 at 01:39:00PM -0700, Matthew Wilcox wrote:
> > The Nehalem system makes an interesting testcase because it exposes some
> > registers in fake PCIe devices that aren't behind the root ports.  eg:
> > 
> > ff:06.3 Host bridge: Intel Corporation Xeon 5500/Core i7 Integrated Memory Controller Channel 2 Thermal Control Registers (rev 04)
> 
> I think these appear as conventional PCI devices; at least the ones
> I've seen, e.g., [1], don't have a PCIe capability, so I think it
> makes sense that they're not behind a root port.
> 
> [1] https://bugzilla5.redhat.com/attachment.cgi?id=433169

Oh, I don't think we're doing anything wrong with how we're displaying
them or what we're doing with what the system presents to us.  My only
point was that this is a good test-case for code which assumes that all
PCI devices lie under a PCIe root port.  At one point during development,
my code reported that device up there as

/06.3 Host bridge: Intel Corporation Xeon 5500/Core i7 Integrated Memory Controller Channel 2 Thermal Control Registers (rev 04)

but since I had that system available to test with, I spotted that problem
and made it present that device as ff:06.3 (both with and without -P).