From 284f5f9dbac170b054c1e386ef92cbf654e91bba Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Mon, 30 Apr 2012 15:21:02 -0600 Subject: [PATCH] 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 +++ arch/x86/pci/common.c | 16 ++++++++++++++++ drivers/pci/pci.c | 3 +++ drivers/pci/probe.c | 8 ++++++-- include/asm-generic/pci-bridge.h | 6 ++++++ 5 files changed, 34 insertions(+), 2 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. diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c index 323481e06ef8..16c5d7835295 100644 --- a/arch/x86/pci/common.c +++ b/arch/x86/pci/common.c @@ -11,6 +11,7 @@ #include #include +#include #include #include #include @@ -229,6 +230,14 @@ static int __devinit assign_all_busses(const struct dmi_system_id *d) } #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 @@ static const struct dmi_system_id __devinitconst pciprobe_dmi_table[] = { DMI_MATCH(DMI_PRODUCT_NAME, "ProLiant DL585 G2"), }, }, + { + .callback = set_scan_all, + .ident = "Stratus/NEC ftServer", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "ftServer"), + }, + }, {} }; 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 #include #include +#include #include #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 #include #include +#include #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; } diff --git a/include/asm-generic/pci-bridge.h b/include/asm-generic/pci-bridge.h index a5b5d5a89a4f..20db2e5a0a69 100644 --- a/include/asm-generic/pci-bridge.h +++ b/include/asm-generic/pci-bridge.h @@ -30,6 +30,12 @@ enum { PCI_ENABLE_PROC_DOMAINS = 0x00000010, /* ... except for domain 0 */ PCI_COMPAT_DOMAIN_0 = 0x00000020, + + /* PCIe downstream ports are bridges that normally lead to only a + * device 0, but if this is set, we scan all possible devices, not + * just device 0. + */ + PCI_SCAN_ALL_PCIE_DEVS = 0x00000040, }; #ifdef CONFIG_PCI -- 2.11.0