From 21bc42ab852549f4a547d18d77e0e4d1b24ffd96 Mon Sep 17 00:00:00 2001 From: Len Brown Date: Tue, 4 Sep 2007 12:49:22 -0400 Subject: ACPI: thermal: use round_jiffies when thermal zone polling is enabled 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 --- drivers/acpi/thermal.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c index bc6d5866ef98..15d5fdc66a96 100644 --- a/drivers/acpi/thermal.c +++ b/drivers/acpi/thermal.c @@ -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)); } } -- cgit v1.2.3