Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751809Ab2KLFmL (ORCPT ); Mon, 12 Nov 2012 00:42:11 -0500 Received: from mga14.intel.com ([143.182.124.37]:37578 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750856Ab2KLFmJ (ORCPT ); Mon, 12 Nov 2012 00:42:09 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.80,759,1344236400"; d="scan'208";a="216332895" Message-ID: <1352698922.1834.1.camel@rzhang1-mobl4> Subject: Re: [PATCH 1/4] thermal: Add new thermal trend type to support quick cooling From: Zhang Rui To: Amit Kachhap Cc: linux-pm@lists.linux-foundation.org, linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org, durgadoss.r@intel.com, lenb@kernel.org, linux-acpi@vger.kernel.org, jonghwa3.lee@samsung.com Date: Mon, 12 Nov 2012 13:42:02 +0800 In-Reply-To: References: <1352348786-24255-1-git-send-email-amit.kachhap@linaro.org> <1352348786-24255-2-git-send-email-amit.kachhap@linaro.org> <1352354503.2190.7.camel@rzhang1-mobl4> <1352433060.2166.3.camel@rzhang1-mobl4> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6840 Lines: 153 On Fri, 2012-11-09 at 11:51 +0530, Amit Kachhap wrote: > On 9 November 2012 09:21, Zhang Rui wrote: > > On Thu, 2012-11-08 at 11:56 +0530, Amit Kachhap wrote: > >> On 8 November 2012 11:31, Zhang Rui 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. > >> > > > hmmm, > > I think a more proper way is to set the cooling state to upper limit > > when it overheats and reduce the cooling state step by step when the > > temperature drops. > > No actually I was thinking of having a simple governor with a feature > like it only sets to upper level and lower level. Also since the > temperature sensor is capable of interrupting for both increase in > threshold(say 100C) and fall in threshold (say 90C), so polling or > step increments is not needed at all. > Currently stepwise governor governor does that so we might change the > macro name as, > THERMAL_TREND_RAISE_STEP, > THERMAL_TREND_DROP_STEP, > THERMAL_TREND_RAISE_MAX, > THERMAL_TREND_DROP_MAX, > > and file step_wise.c can be named as state_wise.c or trend_wise.c. > > I am not sure if it is the best way . How do you feel ? > this sounds good to me. I'd like to see Durga' comments on this as well. thanks, rui > > what do you think? > > > > thanks, > > rui > > > >> > 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 > >> >> Signed-off-by: Amit Daniel Kachhap > >> >> --- > >> >> 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 */ > >> > > >> > > > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/