summaryrefslogtreecommitdiffstats
path: root/drivers/acpi
diff options
context:
space:
mode:
authorLin Ming <ming.m.lin@intel.com>2011-12-13 09:36:03 +0800
committerLen Brown <len.brown@intel.com>2012-01-17 05:25:08 -0500
commitd640113fe80e45ebd4a5b420b220d3f6bf37f682 (patch)
tree5786b877c62ce19e0a282c51d14d69373c2814e6 /drivers/acpi
parent805a6af8dba5dfdd35ec35dc52ec0122400b2610 (diff)
downloadop-kernel-dev-d640113fe80e45ebd4a5b420b220d3f6bf37f682.zip
op-kernel-dev-d640113fe80e45ebd4a5b420b220d3f6bf37f682.tar.gz
ACPI: processor: fix acpi_get_cpuid for UP processor
For UP processor, it is likely that no _MAT method or MADT table defined. So currently acpi_get_cpuid(...) always return -1 for UP processor. This is wrong. It should return valid value for CPU0. In the other hand, BIOS may define multiple CPU handles even for UP processor, for example Scope (_PR) { Processor (CPU0, 0x00, 0x00000410, 0x06) {} Processor (CPU1, 0x01, 0x00000410, 0x06) {} Processor (CPU2, 0x02, 0x00000410, 0x06) {} Processor (CPU3, 0x03, 0x00000410, 0x06) {} } We should only return valid value for CPU0's acpi handle. And return invalid value for others. http://marc.info/?t=132329819900003&r=1&w=2 Cc: stable@vger.kernel.org Reported-and-tested-by: wallak@free.fr Signed-off-by: Lin Ming <ming.m.lin@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/processor_core.c26
1 files changed, 24 insertions, 2 deletions
diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index 3a0428e..c850de4 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -173,8 +173,30 @@ int acpi_get_cpuid(acpi_handle handle, int type, u32 acpi_id)
apic_id = map_mat_entry(handle, type, acpi_id);
if (apic_id == -1)
apic_id = map_madt_entry(type, acpi_id);
- if (apic_id == -1)
- return apic_id;
+ if (apic_id == -1) {
+ /*
+ * On UP processor, there is no _MAT or MADT table.
+ * So above apic_id is always set to -1.
+ *
+ * BIOS may define multiple CPU handles even for UP processor.
+ * For example,
+ *
+ * Scope (_PR)
+ * {
+ * Processor (CPU0, 0x00, 0x00000410, 0x06) {}
+ * Processor (CPU1, 0x01, 0x00000410, 0x06) {}
+ * Processor (CPU2, 0x02, 0x00000410, 0x06) {}
+ * Processor (CPU3, 0x03, 0x00000410, 0x06) {}
+ * }
+ *
+ * Ignores apic_id and always return 0 for CPU0's handle.
+ * Return -1 for other CPU's handle.
+ */
+ if (acpi_id == 0)
+ return acpi_id;
+ else
+ return apic_id;
+ }
#ifdef CONFIG_SMP
for_each_possible_cpu(i) {
OpenPOWER on IntegriCloud