PCI: work around Stratus ftServer broken PCIe hierarchy
authorBjorn Helgaas <bhelgaas@google.com>
Mon, 30 Apr 2012 21:21:02 +0000 (15:21 -0600)
committerBjorn Helgaas <bhelgaas@google.com>
Mon, 30 Apr 2012 21:21:02 +0000 (15:21 -0600)
commit284f5f9dbac170b054c1e386ef92cbf654e91bba
tree74cacc94070d5590378c368fa7378d37319d07be
parent66f75a5d028beaf67c931435fdc3e7823125730c
PCI: work around Stratus ftServer broken PCIe hierarchy

A PCIe downstream port is a P2P bridge.  Its secondary interface is
a link that should lead only to device 0 (unless ARI is enabled)[1], so
we don't probe for non-zero device numbers.

Some Stratus ftServer systems have a PCIe downstream port (02:00.0) that
leads to both an upstream port (03:00.0) and a downstream port (03:01.0),
and 03:01.0 has important devices below it:

  [0000:02]-+-00.0-[03-3c]--+-00.0-[04-09]--...
                            \-01.0-[0a-0d]--+-[USB]
                                            +-[NIC]
                                            +-...

Previously, we didn't enumerate device 03:01.0, so USB and the network
didn't work.  This patch adds a DMI quirk to scan all device numbers,
not just 0, below a downstream port.

Based on a patch by Prarit Bhargava.

[1] PCIe spec r3.0, sec 7.3.1

CC: Myron Stowe <mstowe@redhat.com>
CC: Don Dutile <ddutile@redhat.com>
CC: James Paradis <james.paradis@stratus.com>
CC: Matthew Wilcox <matthew.r.wilcox@intel.com>
CC: Jesse Barnes <jbarnes@virtuousgeek.org>
CC: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Documentation/kernel-parameters.txt
arch/x86/pci/common.c
drivers/pci/pci.c
drivers/pci/probe.c
include/asm-generic/pci-bridge.h