diff options
| author | Len Brown <len.brown@intel.com> | 2007-03-11 03:26:14 -0400 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2007-03-11 03:30:13 -0400 |
| commit | a1fdcc0d2714b6622e3fd5c00db1635213d6c41a (patch) | |
| tree | bf1176f07ff83eebb41d1a292a62124680b81949 /drivers/acpi/tables.c | |
| parent | be521466feb3bb1cd89de82a2b1d080e9ebd3cb6 (diff) | |
| download | linux-a1fdcc0d2714b6622e3fd5c00db1635213d6c41a.tar.bz2 | |
ACPI: Add support to parse 2nd MADT
When a BIOS bug presents multiple APIC/MADTs,
Linux currently uses the 1st and ignores the 2nd.
But some machines work better if we use the 2nd.
http://bugzilla.kernel.org/show_bug.cgi?id=7465
Add a warning and boot parameter "acpi_apic_instance=2"
to allow parsing the 2nd.
No change to default behaviour in this patch.
Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi/tables.c')
| -rw-r--r-- | drivers/acpi/tables.c | 57 |
1 files changed, 52 insertions, 5 deletions
diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c index 849e2c361804..c3419182c9a7 100644 --- a/drivers/acpi/tables.c +++ b/drivers/acpi/tables.c @@ -42,7 +42,9 @@ static char *mps_inti_flags_trigger[] = { "dfl", "edge", "res", "level" }; static struct acpi_table_desc initial_tables[ACPI_MAX_TABLES] __initdata; -void acpi_table_print_madt_entry(struct acpi_subtable_header * header) +static int acpi_apic_instance __initdata; + +void acpi_table_print_madt_entry(struct acpi_subtable_header *header) { if (!header) return; @@ -183,8 +185,10 @@ acpi_table_parse_entries(char *id, if (!handler) return -EINVAL; - /* Locate the table (if exists). There should only be one. */ - acpi_get_table(id, 0, &table_header); + if (strncmp(id, ACPI_SIG_MADT, 4) == 0) + acpi_get_table(id, acpi_apic_instance, &table_header); + else + acpi_get_table(id, 0, &table_header); if (!table_header) { printk(KERN_WARNING PREFIX "%4.4s not present\n", id); @@ -237,10 +241,15 @@ acpi_table_parse_madt(enum acpi_madt_type id, int __init acpi_table_parse(char *id, acpi_table_handler handler) { struct acpi_table_header *table = NULL; + if (!handler) return -EINVAL; - acpi_get_table(id, 0, &table); + if (strncmp(id, ACPI_SIG_MADT, 4) == 0) + acpi_get_table(id, acpi_apic_instance, &table); + else + acpi_get_table(id, 0, &table); + if (table) { handler(table); return 0; @@ -248,6 +257,31 @@ int __init acpi_table_parse(char *id, acpi_table_handler handler) return 1; } +/* + * The BIOS is supposed to supply a single APIC/MADT, + * but some report two. Provide a knob to use either. + * (don't you wish instance 0 and 1 were not the same?) + */ +static void __init check_multiple_madt(void) +{ + struct acpi_table_header *table = NULL; + + acpi_get_table(ACPI_SIG_MADT, 2, &table); + if (table) { + printk(KERN_WARNING PREFIX + "BIOS bug: multiple APIC/MADT found," + " using %d\n", acpi_apic_instance); + printk(KERN_WARNING PREFIX + "If \"acpi_apic_instance=%d\" works better, " + "notify linux-acpi@vger.kernel.org\n", + acpi_apic_instance ? 0 : 2); + + } else + acpi_apic_instance = 0; + + return; +} + /* * acpi_table_init() * @@ -257,9 +291,22 @@ int __init acpi_table_parse(char *id, acpi_table_handler handler) * result: sdt_entry[] is initialized */ - int __init acpi_table_init(void) { acpi_initialize_tables(initial_tables, ACPI_MAX_TABLES, 0); + check_multiple_madt(); + return 0; +} + +static int __init acpi_parse_apic_instance(char *str) +{ + + acpi_apic_instance = simple_strtoul(str, NULL, 0); + + printk(KERN_NOTICE PREFIX "Shall use APIC/MADT table %d\n", + acpi_apic_instance); + return 0; } + +early_param("acpi_apic_instance", acpi_parse_apic_instance); |