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authorBjorn Helgaas <bhelgaas@google.com>2012-04-30 15:21:02 -0600
committerBjorn Helgaas <bhelgaas@google.com>2012-04-30 15:21:02 -0600
commit284f5f9dbac170b054c1e386ef92cbf654e91bba (patch)
tree74cacc94070d5590378c368fa7378d37319d07be /drivers/pci/probe.c
parent66f75a5d028beaf67c931435fdc3e7823125730c (diff)
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 'drivers/pci/probe.c')
-rw-r--r--drivers/pci/probe.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 5e1ca3c58a7..2dc8675eea1 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -10,6 +10,7 @@
#include <linux/module.h>
#include <linux/cpumask.h>
#include <linux/pci-aspm.h>
+#include <asm-generic/pci-bridge.h>
#include "pci.h"
#define CARDBUS_LATENCY_TIMER 176 /* secondary latency timer */
@@ -1395,10 +1396,13 @@ static unsigned no_next_fn(struct pci_dev *dev, unsigned fn)
static int only_one_child(struct pci_bus *bus)
{
struct pci_dev *parent = bus->self;
+
if (!parent || !pci_is_pcie(parent))
return 0;
- if (parent->pcie_type == PCI_EXP_TYPE_ROOT_PORT ||
- parent->pcie_type == PCI_EXP_TYPE_DOWNSTREAM)
+ if (parent->pcie_type == PCI_EXP_TYPE_ROOT_PORT)
+ return 1;
+ if (parent->pcie_type == PCI_EXP_TYPE_DOWNSTREAM &&
+ !pci_has_flag(PCI_SCAN_ALL_PCIE_DEVS))
return 1;
return 0;
}