On Friday, July 20, 2012, Jacob Pan wrote:
> On Thu, 19 Jul 2012 14:31:11 +0800
> Zhang Rui <rui.zhang@xxxxxxxxx> wrote:
>
> > tc1 and tc2 are used by OSPM to anticipate the temperature trends.
> > But they are ACPI platform specific concepts.
> >
> > Introduce .get_trend() as a more general solution.
> >
> > Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> > ---
> > drivers/acpi/thermal.c | 30 ++++++++++++++++++++++++++++++
> > drivers/thermal/thermal_sys.c | 19 +++++++++++++++++--
> > include/linux/thermal.h | 9 +++++++++
> > 3 files changed, 56 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
> > index a7c97f5..b345646 100644
> > --- a/drivers/acpi/thermal.c
> > +++ b/drivers/acpi/thermal.c
> > @@ -704,6 +704,35 @@ static int thermal_get_crit_temp(struct
> > thermal_zone_device *thermal, return -EINVAL;
> > }
> >
> > +static int thermal_get_trend(struct thermal_zone_device *thermal,
> > + int trip, enum thermal_trend *trend)
> > +{
> > + struct acpi_thermal *tz = thermal->devdata;
> > + enum thermal_trip_type type;
> > + unsigned long trip_temp;
> > + int i;
> > +
> > + if (thermal_get_trip_type(thermal, trip, &type))
> > + return -EINVAL;
> > +
> > + /* Only PASSIVE trip points need TREND */
> > + if (type != THERMAL_TRIP_PASSIVE)
> > + return -EINVAL;
> > +
> > + /*
> > + * tz->temperature has already been updated by generic
> > thermal layer,
> > + * before this callback being invoked
> > + */
> > + i = (tz->trips.passive.tc1 * (tz->temperature -
> > tz->last_temperature))
> > + + (tz->trips.passive.tc2
> > + * (tz->temperature - tz->trips.passive.temperature));
> > +
> > + *trend = i > 0 ? THERMAL_TREND_RAISING :
> > + (i < 0 ? THERMAL_TREND_DROPPING :
> > THERMAL_TREND_STABLE);
> > + return 0;
> > +}
> > +
> > +
> > static int thermal_notify(struct thermal_zone_device *thermal, int
> > trip, enum thermal_trip_type trip_type)
> > {
> > @@ -832,6 +861,7 @@ static const struct thermal_zone_device_ops
> > acpi_thermal_zone_ops = { .get_trip_type = thermal_get_trip_type,
> > .get_trip_temp = thermal_get_trip_temp,
> > .get_crit_temp = thermal_get_crit_temp,
> > + .get_trend = thermal_get_trend,
> > .notify = thermal_notify,
> > };
> >
> > diff --git a/drivers/thermal/thermal_sys.c
> > b/drivers/thermal/thermal_sys.c index db35300..29b6dba 100644
> > --- a/drivers/thermal/thermal_sys.c
> > +++ b/drivers/thermal/thermal_sys.c
> > @@ -698,6 +698,18 @@ thermal_remove_hwmon_sysfs(struct
> > thermal_zone_device *tz) }
> > #endif
> >
> > +static void thermal_get_trend(struct thermal_zone_device *tz,
> > + int trip, enum thermal_trend *trend)
> > +{
> > + if (tz->ops->get_trend)
> > + if (!tz->ops->get_trend(tz, trip, trend))
> > + return;
> > +
> > + *trend = tz->temperature >= tz->last_temperature ?
> > + THERMAL_TREND_RAISING : THERMAL_TREND_DROPPING;
> I think you are mixing things a little here. ACPI passive cooling
> formula generates a performance trend to guide thermal management,
> which is not a simple temperature trend.
>
> In case of no .get_trend() present, caller can easily figure out
> temperature trend explicitly instead of getting uninformed information.
thermal_zone_device_passive() (below) is the caller and I don't think it
can really do that.
That said, since thermal_zone_device_passive() seems to me the only caller of
thermal_get_trend(), it might be better to move the code to that function
directly.
Thanks,
Rafael
> > + return;
> > +}
> > +
> > static void thermal_zone_device_set_polling(struct
> > thermal_zone_device *tz, int delay)
> > {
> > @@ -732,6 +744,8 @@ static void thermal_zone_device_passive(struct
> > thermal_zone_device *tz, if (temp >= trip_temp) {
> > tz->passive = true;
> >
> > + thermal_get_trend(tz, trip, (enum thermal_trend
> > *)&trend); +
> > trend = (tz->tc1 * (temp - tz->last_temperature)) +
> > (tz->tc2 * (temp - trip_temp));
> >
> > @@ -1090,6 +1104,9 @@ void thermal_zone_device_update(struct
> > thermal_zone_device *tz) goto leave;
> > }
> >
> > + tz->last_temperature = tz->temperature;
> > + tz->temperature = temp;
> > +
> > for (count = 0; count < tz->trips; count++) {
> > tz->ops->get_trip_type(tz, count, &trip_type);
> > tz->ops->get_trip_temp(tz, count, &trip_temp);
> > @@ -1149,8 +1166,6 @@ void thermal_zone_device_update(struct
> > thermal_zone_device *tz) thermal_zone_device_passive(tz, temp,
> > tz->forced_passive, THERMAL_TRIPS_NONE);
> >
> > - tz->last_temperature = temp;
> > -
> > leave:
> > if (tz->passive)
> > thermal_zone_device_set_polling(tz,
> > tz->passive_delay); diff --git a/include/linux/thermal.h
> > b/include/linux/thermal.h index b355c62..ab656d6 100644
> > --- a/include/linux/thermal.h
> > +++ b/include/linux/thermal.h
> > @@ -44,6 +44,12 @@ enum thermal_trip_type {
> > THERMAL_TRIP_CRITICAL,
> > };
> >
> > +enum thermal_trend {
> > + THERMAL_TREND_STABLE, /* temperature is stable */
> > + THERMAL_TREND_RAISING, /* temperature is raising */
> > + THERMAL_TREND_DROPPING, /* temperature is dropping */
> > +};
> > +
> > struct thermal_zone_device_ops {
> > int (*bind) (struct thermal_zone_device *,
> > struct thermal_cooling_device *);
> > @@ -65,6 +71,8 @@ struct thermal_zone_device_ops {
> > int (*set_trip_hyst) (struct thermal_zone_device *, int,
> > unsigned long);
> > int (*get_crit_temp) (struct thermal_zone_device *, unsigned
> > long *);
> > + int (*get_trend) (struct thermal_zone_device *, int,
> > + enum thermal_trend *);
> > int (*notify) (struct thermal_zone_device *, int,
> > enum thermal_trip_type);
> > };
> > @@ -109,6 +117,7 @@ struct thermal_zone_device {
> > int tc2;
> > int passive_delay;
> > int polling_delay;
> > + int temperature;
> > int last_temperature;
> > bool passive;
> > unsigned int forced_passive;
>
>
>
>
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