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authorBjorn Helgaas <bhelgaas@google.com>2012-05-01 01:21:02 +0400
committerBjorn Helgaas <bhelgaas@google.com>2012-05-01 01:21:02 +0400
commit284f5f9dbac170b054c1e386ef92cbf654e91bba (patch)
tree74cacc94070d5590378c368fa7378d37319d07be /Documentation/kernel-parameters.txt
parent66f75a5d028beaf67c931435fdc3e7823125730c (diff)
downloadlinux-284f5f9dbac170b054c1e386ef92cbf654e91bba.tar.xz
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>
Diffstat (limited to 'Documentation/kernel-parameters.txt')
-rw-r--r--Documentation/kernel-parameters.txt3
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index c1601e5a8b71..f995195409fd 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2161,6 +2161,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
on: Turn realloc on
realloc same as realloc=on
noari do not use PCIe ARI.
+ pcie_scan_all Scan all possible PCIe devices. Otherwise we
+ only look for one device below a PCIe downstream
+ port.
pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power
Management.