ACPI: thermal: use round_jiffies when thermal zone polling is enabled (21bc42ab) · Commits · 戴 / test

Properly functioning systems do not use thermal zone polling, they use event-based notification. However, some users enable periodic thermal zone polling to work around bugs on their platforms, and at least one platform exists with a real _TZP that requests polling. While thermal zone polling (_TZP) is specified in units to 0.1 seconds, it actually has a maximum granularity of 1 second. Thus, we can safely round up the _TZP timeout to occur on the next 1-second boundary. This will batch it with other 1-second-granularity timers in the system and thus potentially extend processor idle duration. Note that the same timer is used both for _TZP and for passive processor thermal throttling. We can not round up the timeout when it is used for passive thermal throttling. Also, we can not make this a deferrable timer, as temperature is just as relevant during idle as it is during non-idle. Signed-off-by:

Len Brown <len.brown@intel.com>

drivers/acpi/thermal.c

+8 −5

Original line number	Diff line number	Diff line
		@@ -711,6 +711,7 @@ static void acpi_thermal_check(void *data)
		int result = 0;
		struct acpi_thermal *tz = data;
		unsigned long sleep_time = 0;
		unsigned long timeout_jiffies = 0;
		int i = 0;
		struct acpi_thermal_state state;

		@@ -787,10 +788,13 @@ static void acpi_thermal_check(void *data)
		* a thermal event occurs). Note that _TSP and _TZD values are
		* given in 1/10th seconds (we must covert to milliseconds).
		*/
		if (tz->state.passive)
		if (tz->state.passive) {
		sleep_time = tz->trips.passive.tsp * 100;
		else if (tz->polling_frequency > 0)
		timeout_jiffies = jiffies + (HZ * sleep_time) / 1000;
		} else if (tz->polling_frequency > 0) {
		sleep_time = tz->polling_frequency * 100;
		timeout_jiffies = round_jiffies(jiffies + (HZ * sleep_time) / 1000);
		}

		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "%s: temperature[%lu] sleep[%lu]\n",
		tz->name, tz->temperature, sleep_time));
		@@ -804,12 +808,11 @@ static void acpi_thermal_check(void *data)
		del_timer(&(tz->timer));
		} else {
		if (timer_pending(&(tz->timer)))
		mod_timer(&(tz->timer),
		jiffies + (HZ * sleep_time) / 1000);
		mod_timer(&(tz->timer), timeout_jiffies);
		else {
		tz->timer.data = (unsigned long)tz;
		tz->timer.function = acpi_thermal_run;
		tz->timer.expires = jiffies + (HZ * sleep_time) / 1000;
		tz->timer.expires = timeout_jiffies;
		add_timer(&(tz->timer));
		}
		}

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