Commit 284f5f9d authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

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: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 66f75a5d

Documentation/kernel-parameters.txt

+3 −0
Original line number Diff line number Diff line
@@ -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.

arch/x86/pci/common.c

+16 −0
Original line number Diff line number Diff line
@@ -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 @@ 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"),

		},

	},

	{}

};

drivers/pci/pci.c

+3 −0
Original line number Diff line number Diff line
@@ -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);

drivers/pci/probe.c

+6 −2
Original line number Diff line number Diff line
@@ -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;

}

include/asm-generic/pci-bridge.h

+6 −0
Original line number Diff line number Diff line
@@ -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

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