[PATCH v3 4/7] x86/PCI: use host bridge _CRS info by default on 2008 and newer machines

Bjorn Helgaas
2010-02-12T17:00:19Z

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: Bjorn Helgaas <bjorn.helgaas@hp.com>
---

Documentation/kernel-parameters.txt | 8 ++++-
arch/ia64/include/asm/acpi.h | 1 +
arch/x86/include/asm/pci_x86.h | 1 +
arch/x86/pci/acpi.c | 53 +++++++++++++++++++++++++++++++----
arch/x86/pci/common.c | 3 ++
drivers/acpi/pci_root.c | 1 +
include/acpi/acpi_drivers.h | 1 +
7 files changed, 60 insertions(+), 8 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 01e2a98..6913e9a 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1939,8 +1939,12 @@ 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
diff --git a/arch/ia64/include/asm/acpi.h b/arch/ia64/include/asm/acpi.h
index 7ae5889..7f2d7f2 100644
--- a/arch/ia64/include/asm/acpi.h
+++ b/arch/ia64/include/asm/acpi.h
@@ -97,6 +97,7 @@ 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);
diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h
index b4bf9a9..05b58cc 100644
--- a/arch/x86/include/asm/pci_x86.h
+++ b/arch/x86/include/asm/pci_x86.h
@@ -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;
diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index a2f8cdb..5f11ff6 100644
--- a/arch/x86/pci/acpi.c
+++ b/arch/x86/pci/acpi.c
@@ -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;
diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
index d2552c6..3736176 100644
--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -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;
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 64ae2f2..4a46051 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -566,6 +566,7 @@ static int __init acpi_pci_root_init(void)
if (acpi_pci_disabled)
return 0;

+ pci_acpi_crs_quirks();
if (acpi_bus_register_driver(&acpi_pci_root_driver) < 0)
return -ENODEV;

diff --git a/include/acpi/acpi_drivers.h b/include/acpi/acpi_drivers.h
index f4906f6..3a4767c 100644
--- a/include/acpi/acpi_drivers.h
+++ b/include/acpi/acpi_drivers.h
@@ -104,6 +104,7 @@ int acpi_pci_bind_root(struct acpi_device *device);

struct pci_bus *pci_acpi_scan_root(struct acpi_device *device, int domain,
int bus);
+void pci_acpi_crs_quirks(void);

/* --------------------------------------------------------------------------
Processor