From: Len Brown <len.brown@xxxxxxxxx>
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@xxxxxxxxx>
---
drivers/acpi/thermal.c | 13 ++++++++-----
1 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
index bc6d586..15d5fdc 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));
}
}
--
1.5.3.4.206.g58ba4
-
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