ACPI processor: introduce module parameter processor.ignore_tpc
Introduce module parameter processor.ignore_tpc.
Some laptops are shipped with buggy _TPC,
this module parameter is used to to disable the buggy support.
http://bugzilla.kernel.org/show_bug.cgi?id=13259
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Tested-by: James Ettle <theholyettlz@googlemail.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c
index d0d1f4d..5f09fb8 100644
--- a/drivers/acpi/processor_throttling.c
+++ b/drivers/acpi/processor_throttling.c
@@ -45,6 +45,14 @@
#define _COMPONENT ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("processor_throttling");
+/* ignore_tpc:
+ * 0 -> acpi processor driver doesn't ignore _TPC values
+ * 1 -> acpi processor driver ignores _TPC values
+ */
+static int ignore_tpc;
+module_param(ignore_tpc, int, 0644);
+MODULE_PARM_DESC(ignore_tpc, "Disable broken BIOS _TPC throttling support");
+
struct throttling_tstate {
unsigned int cpu; /* cpu nr */
int target_state; /* target T-state */
@@ -283,6 +291,10 @@
if (!pr)
return -EINVAL;
+
+ if (ignore_tpc)
+ goto end;
+
status = acpi_evaluate_integer(pr->handle, "_TPC", NULL, &tpc);
if (ACPI_FAILURE(status)) {
if (status != AE_NOT_FOUND) {
@@ -290,6 +302,8 @@
}
return -ENODEV;
}
+
+end:
pr->throttling_platform_limit = (int)tpc;
return 0;
}
@@ -302,6 +316,9 @@
struct acpi_processor_limit *limit;
int target_state;
+ if (ignore_tpc)
+ return 0;
+
result = acpi_processor_get_platform_limit(pr);
if (result) {
/* Throttling Limit is unsupported */