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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 /drivers/pci
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 'drivers/pci')
-rw-r--r--drivers/pci/pci.c3
-rw-r--r--drivers/pci/probe.c8
2 files changed, 9 insertions, 2 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 111569ccab43..8e6c38817036 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -22,6 +22,7 @@
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/pm_runtime.h>
+#include <asm-generic/pci-bridge.h>
#include <asm/setup.h>
#include "pci.h"
@@ -3893,6 +3894,8 @@ static int __init pci_setup(char *str)
pcie_bus_config = PCIE_BUS_PERFORMANCE;
} else if (!strncmp(str, "pcie_bus_peer2peer", 18)) {
pcie_bus_config = PCIE_BUS_PEER2PEER;
+ } else if (!strncmp(str, "pcie_scan_all", 13)) {
+ pci_add_flags(PCI_SCAN_ALL_PCIE_DEVS);
} else {
printk(KERN_ERR "PCI: Unknown option `%s'\n",
str);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 5e1ca3c58a7d..2dc8675eea1a 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;
}