Subject: ACPI :Add the _TPC throttling limit for TSS
>From : Zhao Yakui <yakui.zhao@xxxxxxxxx>
When T-state limit change notification is received, OSPM should
evaluate the _TPC object and change the current T-State according to the new
limit.
Signed-off-by: Zhao Yakui <yakui.zhao@xxxxxxxxx>
Signed-off-by: Li Shaohua <shaohua.li@xxxxxxxxx>
---
drivers/acpi/processor_throttling.c | 49 +++++++++++++++++++++++++++++++++++-
1 file changed, 48 insertions(+), 1 deletion(-)
Index: linux-2.6.24-rc1/drivers/acpi/processor_throttling.c
===================================================================
--- linux-2.6.24-rc1.orig/drivers/acpi/processor_throttling.c
+++ linux-2.6.24-rc1/drivers/acpi/processor_throttling.c
@@ -70,7 +70,54 @@ static int acpi_processor_get_platform_l
int acpi_processor_tstate_has_changed(struct acpi_processor *pr)
{
- return acpi_processor_get_platform_limit(pr);
+ int result = 0;
+ int throttling_limit;
+ int current_state;
+ struct acpi_processor_limit *limit;
+ int target_state;
+
+ result = acpi_processor_get_platform_limit(pr);
+ if (result) {
+ /* Throttling Limit is unsupported */
+ return result;
+ }
+
+ throttling_limit = pr->throttling_platform_limit;
+ if (throttling_limit >= pr->throttling.state_count) {
+ /* Uncorrect Throttling Limit */
+ return -EINVAL;
+ }
+
+ current_state = pr->throttling.state;
+ if (current_state >= throttling_limit) {
+ /*
+ * The current state can meet with the requirement of
+ * _TPC limit. But it is reasonable that OSPM changes
+ * t-states from high to low for better performance.
+ * Of course the limit condition of thermal
+ * and user should be considered.
+ */
+ limit = &pr->limit;
+ target_state = throttling_limit;
+ if (limit->thermal.tx > target_state)
+ target_state = limit->thermal.tx;
+ if (limit->user.tx > target_state)
+ target_state = limit->user.tx;
+ if (target_state == current_state) {
+ /* unnecessary to change T-state */
+ return 0;
+ }
+ } else {
+ /*
+ * If the current state is lower than the limit of _TPC, it
+ * will be forced to switch to the throttling state defined
+ * by throttling_platfor_limit.
+ * Because the previous state meets with the limit condition
+ * of thermal and user, it is unnecessary to check it again.
+ */
+ target_state = throttling_limit;
+ }
+ return acpi_processor_set_throttling(pr, target_state);
}
/*
-
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