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ACPI: Reevaluate whether the T-state is supported or not after cpu is online/offline

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After one CPU is offlined, it is unnecessary to switch T-state for it.
So it will be better that the throttling is disabled after the cpu
is offline.
At the same time after one cpu is online, we should check whether
the T-state is supported and then set the corresponding T-state
flag.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Zhao Yakui
2011-01-10 16:35:45 +08:00
committed by Len Brown
parent daef1f35ea
commit 5a344a5050
3 changed files with 63 additions and 0 deletions
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52
drivers/acpi/processor_throttling.c
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@ -369,6 +369,58 @@ int acpi_processor_tstate_has_changed(struct acpi_processor *pr)
return acpi_processor_set_throttling(pr, target_state, false);
}
/*
* This function is used to reevaluate whether the T-state is valid
* after one CPU is onlined/offlined.
* It is noted that it won't reevaluate the following properties for
* the T-state.
* 1. Control method.
* 2. the number of supported T-state
* 3. TSD domain
*/
void acpi_processor_reevaluate_tstate(struct acpi_processor *pr,
unsigned long action)
{
int result = 0;
if (action == CPU_DEAD) {
/* When one CPU is offline, the T-state throttling
* will be invalidated.
*/
pr->flags.throttling = 0;
return;
}
/* the following is to recheck whether the T-state is valid for
* the online CPU
*/
if (!pr->throttling.state_count) {
/* If the number of T-state is invalid, it is
* invalidated.
*/
pr->flags.throttling = 0;
return;
}
pr->flags.throttling = 1;
/* Disable throttling (if enabled). We'll let subsequent
* policy (e.g.thermal) decide to lower performance if it
* so chooses, but for now we'll crank up the speed.
*/
result = acpi_processor_get_throttling(pr);
if (result)
goto end;
if (pr->throttling.state) {
result = acpi_processor_set_throttling(pr, 0, false);
if (result)
goto end;
}
end:
if (result)
pr->flags.throttling = 0;
}
/*
* _PTC - Processor Throttling Control (and status) register location
*/