Hi Rui/Amit, Sorry for the late response.. > -----Original Message----- > From: Amit Kachhap [mailto:amit.kachhap@xxxxxxxxxx] > Sent: Thursday, November 08, 2012 11:56 AM > To: Zhang, Rui > Cc: linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-samsung- > soc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; R, Durgadoss; > lenb@xxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; jonghwa3.lee@xxxxxxxxxxx > Subject: Re: [PATCH 1/4] thermal: Add new thermal trend type to support > quick cooling > > On 8 November 2012 11:31, Zhang Rui <rui.zhang@xxxxxxxxx> wrote: > > On Thu, 2012-11-08 at 09:56 +0530, Amit Daniel Kachhap wrote: > >> This modification adds 2 new thermal trend type > THERMAL_TREND_RAISE_FULL > >> and THERMAL_TREND_DROP_FULL. This thermal trend can be used to > quickly > >> jump to the upper or lower cooling level instead of incremental increase > >> or decrease. > > > > IMO, what we need is a new more aggressive cooling governor which > always > > uses upper limit when the temperature is raising and lower limit when > > the temperature is dropping. > Yes I agree that a new aggressive governor is the best approach but > then i thought adding a new trend type is a simple solution to achieve > this and since most of the governor logic might be same as the > step-wise governor. I have no objection in doing it through governor. Yes, this sounds like a feasible and not-so-complicated implementation for now. In future, if we see a lot of drivers requiring this sudden raise/drop functionality, at that time we can introduce an 'aggressive' governor. Thanks, Durga > > > > I can write such a governor if you do not have time to. > ok. thanks > > > > thanks, > > rui > >> This is needed for temperature sensors which support rising/falling > >> threshold interrupts and polling can be totally avoided. > >> > > > > > >> Signed-off-by: Amit Daniel Kachhap <amit.daniel@xxxxxxxxxxx> > >> Signed-off-by: Amit Daniel Kachhap <amit.kachhap@xxxxxxxxxx> > >> --- > >> drivers/thermal/step_wise.c | 19 +++++++++++++++---- > >> include/linux/thermal.h | 2 ++ > >> 2 files changed, 17 insertions(+), 4 deletions(-) > >> > >> diff --git a/drivers/thermal/step_wise.c b/drivers/thermal/step_wise.c > >> index 1242cff..0d2d8d6 100644 > >> --- a/drivers/thermal/step_wise.c > >> +++ b/drivers/thermal/step_wise.c > >> @@ -35,6 +35,10 @@ > >> * state for this trip point > >> * b. if the trend is THERMAL_TREND_DROPPING, use lower cooling > >> * state for this trip point > >> + * c. if the trend is THERMAL_TREND_RAISE_FULL, use highest cooling > >> + * state for this trip point > >> + * d. if the trend is THERMAL_TREND_DROP_FULL, use lowest cooling > >> + * state for this trip point > >> */ > >> static unsigned long get_target_state(struct thermal_instance *instance, > >> enum thermal_trend trend) > >> @@ -50,7 +54,10 @@ static unsigned long get_target_state(struct > thermal_instance *instance, > >> } else if (trend == THERMAL_TREND_DROPPING) { > >> cur_state = cur_state > instance->lower ? > >> (cur_state - 1) : instance->lower; > >> - } > >> + } else if (trend == THERMAL_TREND_RAISE_FULL) > >> + cur_state = instance->upper; > >> + else if (trend == THERMAL_TREND_DROP_FULL) > >> + cur_state = instance->lower; > >> > >> return cur_state; > >> } > >> @@ -87,7 +94,8 @@ static void update_instance_for_throttle(struct > thermal_zone_device *tz, > >> } > >> > >> static void update_instance_for_dethrottle(struct thermal_zone_device > *tz, > >> - int trip, enum thermal_trip_type trip_type) > >> + int trip, enum thermal_trip_type trip_type, > >> + enum thermal_trend trend) > >> { > >> struct thermal_instance *instance; > >> struct thermal_cooling_device *cdev; > >> @@ -101,7 +109,10 @@ static void > update_instance_for_dethrottle(struct thermal_zone_device *tz, > >> cdev = instance->cdev; > >> cdev->ops->get_cur_state(cdev, &cur_state); > >> > >> - instance->target = cur_state > instance->lower ? > >> + if (trend == THERMAL_TREND_DROP_FULL) > >> + instance->target = instance->lower; > >> + else > >> + instance->target = cur_state > instance->lower ? > >> (cur_state - 1) : THERMAL_NO_TARGET; > >> > >> /* Deactivate a passive thermal instance */ > >> @@ -133,7 +144,7 @@ static void thermal_zone_trip_update(struct > thermal_zone_device *tz, int trip) > >> if (tz->temperature >= trip_temp) > >> update_instance_for_throttle(tz, trip, trip_type, trend); > >> else > >> - update_instance_for_dethrottle(tz, trip, trip_type); > >> + update_instance_for_dethrottle(tz, trip, trip_type, trend); > >> > >> mutex_unlock(&tz->lock); > >> } > >> diff --git a/include/linux/thermal.h b/include/linux/thermal.h > >> index 807f214..8bce3ec 100644 > >> --- a/include/linux/thermal.h > >> +++ b/include/linux/thermal.h > >> @@ -68,6 +68,8 @@ enum thermal_trend { > >> THERMAL_TREND_STABLE, /* temperature is stable */ > >> THERMAL_TREND_RAISING, /* temperature is raising */ > >> THERMAL_TREND_DROPPING, /* temperature is dropping */ > >> + THERMAL_TREND_RAISE_FULL, /* Apply highest cooling action*/ > >> + THERMAL_TREND_DROP_FULL, /* Apply lowest cooling action*/ > >> }; > >> > >> /* Events supported by Thermal Netlink */ > > > >
