Subject: ACPI :Add the _TPC throttling limit for TSS
>From : Zhao Yakui <[EMAIL PROTECTED]>

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 <[EMAIL PROTECTED]>
Signed-off-by: Li Shaohua <[EMAIL PROTECTED]>

---
 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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