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Commit 7bc5e3f2 authored by Bjorn Helgaas's avatar Bjorn Helgaas Committed by Jesse Barnes
Browse files

x86/PCI: use host bridge _CRS info by default on 2008 and newer machines 

The main benefit of using ACPI host bridge window information is that
we can do better resource allocation in systems with multiple host bridges,
e.g., http://bugzilla.kernel.org/show_bug.cgi?id=14183

Sometimes we need _CRS information even if we only have one host bridge,
e.g., https://bugs.launchpad.net/ubuntu/+source/linux/+bug/341681



Most of these systems are relatively new, so this patch turns on
"pci=use_crs" only on machines with a BIOS date of 2008 or newer.

Signed-off-by: default avatarBjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
parent 2fe2abf8

Documentation/kernel-parameters.txt

+6 −2
Original line number Diff line number Diff line
@@ -1948,8 +1948,12 @@ and is between 256 and 4096 characters. It is defined in the file 
				IRQ routing is enabled.

		noacpi		[X86] Do not use ACPI for IRQ routing

				or for PCI scanning.

		use_crs		[X86] Use _CRS for PCI resource

				allocation.

		use_crs		[X86] Use PCI host bridge window information

				from ACPI.  On BIOSes from 2008 or later, this

				is enabled by default.  If you need to use this,

				please report a bug.

		nocrs		[X86] Ignore PCI host bridge windows from ACPI.

			        If you need to use this, please report a bug.

		routeirq	Do IRQ routing for all PCI devices.

				This is normally done in pci_enable_device(),

				so this option is a temporary workaround

arch/ia64/include/asm/acpi.h

+1 −0
Original line number Diff line number Diff line
@@ -98,6 +98,7 @@ ia64_acpi_release_global_lock (unsigned int *lock) 
#endif

#define acpi_processor_cstate_check(x) (x) /* no idle limits on IA64 :) */

static inline void disable_acpi(void) { }

static inline void pci_acpi_crs_quirks(void) { }



const char *acpi_get_sysname (void);

int acpi_request_vector (u32 int_type);

arch/x86/include/asm/pci_x86.h

+1 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#define PCI_CHECK_ENABLE_AMD_MMCONF	0x20000

#define PCI_HAS_IO_ECS		0x40000

#define PCI_NOASSIGN_ROMS	0x80000

#define PCI_ROOT_NO_CRS		0x100000



extern unsigned int pci_probe;

extern unsigned long pirq_table_addr;

arch/x86/pci/acpi.c

+47 −6
Original line number Diff line number Diff line
@@ -15,6 +15,51 @@ struct pci_root_info { 
	int busnum;

};



static bool pci_use_crs = true;



static int __init set_use_crs(const struct dmi_system_id *id)

{

	pci_use_crs = true;

	return 0;

}



static const struct dmi_system_id pci_use_crs_table[] __initconst = {

	/* http://bugzilla.kernel.org/show_bug.cgi?id=14183 */

	{

		.callback = set_use_crs,

		.ident = "IBM System x3800",

		.matches = {

			DMI_MATCH(DMI_SYS_VENDOR, "IBM"),

			DMI_MATCH(DMI_PRODUCT_NAME, "x3800"),

		},

	},

	{}

};



void __init pci_acpi_crs_quirks(void)

{

	int year;



	if (dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL) && year < 2008)

		pci_use_crs = false;



	dmi_check_system(pci_use_crs_table);



	/*

	 * If the user specifies "pci=use_crs" or "pci=nocrs" explicitly, that

	 * takes precedence over anything we figured out above.

	 */

	if (pci_probe & PCI_ROOT_NO_CRS)

		pci_use_crs = false;

	else if (pci_probe & PCI_USE__CRS)

		pci_use_crs = true;



	printk(KERN_INFO "PCI: %s host bridge windows from ACPI; "

	       "if necessary, use \"pci=%s\" and report a bug\n",

	       pci_use_crs ? "Using" : "Ignoring",

	       pci_use_crs ? "nocrs" : "use_crs");

}



static acpi_status

resource_to_addr(struct acpi_resource *resource,

			struct acpi_resource_address64 *addr)
@@ -106,7 +151,7 @@ setup_resource(struct acpi_resource *acpi_res, void *data) 
	res->child = NULL;

	align_resource(info->bridge, res);



	if (!(pci_probe & PCI_USE__CRS)) {

	if (!pci_use_crs) {

		dev_printk(KERN_DEBUG, &info->bridge->dev,

			   "host bridge window %pR (ignored)\n", res);

		return AE_OK;
@@ -137,12 +182,8 @@ get_current_resources(struct acpi_device *device, int busnum, 
	struct pci_root_info info;

	size_t size;



	if (pci_probe & PCI_USE__CRS)

	if (pci_use_crs)

		pci_bus_remove_resources(bus);

	else

		dev_info(&device->dev,

			 "ignoring host bridge windows from ACPI; "

			 "boot with \"pci=use_crs\" to use them\n");



	info.bridge = device;

	info.bus = bus;

arch/x86/pci/common.c

+3 −0
Original line number Diff line number Diff line
@@ -520,6 +520,9 @@ char * __devinit pcibios_setup(char *str) 
	} else if (!strcmp(str, "use_crs")) {

		pci_probe |= PCI_USE__CRS;

		return NULL;

	} else if (!strcmp(str, "nocrs")) {

		pci_probe |= PCI_ROOT_NO_CRS;

		return NULL;

	} else if (!strcmp(str, "earlydump")) {

		pci_early_dump_regs = 1;

		return NULL;