From 284f5f9dbac170b054c1e386ef92cbf654e91bba Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Mon, 30 Apr 2012 15:21:02 -0600 Subject: 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 CC: Don Dutile CC: James Paradis CC: Matthew Wilcox CC: Jesse Barnes CC: Prarit Bhargava Signed-off-by: Bjorn Helgaas --- Documentation/kernel-parameters.txt | 3 +++ 1 file changed, 3 insertions(+) (limited to 'Documentation/kernel-parameters.txt') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index c1601e5a8b7..f995195409f 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. -- cgit v1.2.3