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>diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
index 323481e..16c5d78 100644
--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -11,6 +11,7 @@
#include <linux/dmi.h>
#include <linux/slab.h>
+#include <asm-generic/pci-bridge.h>
#include <asm/acpi.h>
#include <asm/segment.h>
#include <asm/io.h>
@@ -229,6 +230,14 @@
}
#endif
+static int __devinit set_scan_all(const struct dmi_system_id *d)
+{
+ printk(KERN_INFO "PCI: %s detected, enabling pci=pcie_scan_all\n",
+ d->ident);
+ pci_add_flags(PCI_SCAN_ALL_PCIE_DEVS);
+ return 0;
+}
+
static const struct dmi_system_id __devinitconst pciprobe_dmi_table[] = {
#ifdef __i386__
/*
@@ -420,6 +429,13 @@
DMI_MATCH(DMI_PRODUCT_NAME, "ProLiant DL585 G2"),
},
},
+ {
+ .callback = set_scan_all,
+ .ident = "Stratus/NEC ftServer",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "ftServer"),
+ },
+ },
{}
};
