Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751869AbbLaSoL (ORCPT ); Thu, 31 Dec 2015 13:44:11 -0500 Received: from mail-pf0-f182.google.com ([209.85.192.182]:32866 "EHLO mail-pf0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750857AbbLaSoI (ORCPT ); Thu, 31 Dec 2015 13:44:08 -0500 Date: Thu, 31 Dec 2015 10:43:55 -0800 From: Eduardo Valentin To: Chen Yu Cc: rui.zhang@intel.com, javi.merino@arm.com, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH 1/3][v3] Thermal: initialize thermal zone device correctly Message-ID: <20151231184344.GB14127@localhost.localdomain> References: <3e6dafce0f659ca2510750f1e03dbba4bc5767c9.1446192980.git.yu.c.chen@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3e6dafce0f659ca2510750f1e03dbba4bc5767c9.1446192980.git.yu.c.chen@intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6291 Lines: 166 For some reason, I thought Rui had picked this already. Anyways, here are a couple of comments: On Fri, Oct 30, 2015 at 04:31:47PM +0800, Chen Yu wrote: > From: Zhang Rui > > After thermal zone device registered, as we have not read any > temperature before, thus tz->temperature should not be 0, > which actually means 0C, and thermal trend is not available. > In this case, we need specially handling for the first > thermal_zone_device_update(). > > Both thermal core framework and step_wise governor is > enhanced to handle this. And since the step_wise governor > is the only one that uses trends, so it's the only thermal > governor that needs to be updated. > > CC: #3.18+ > Tested-by: Manuel Krause > Tested-by: szegad > Tested-by: prash > Tested-by: amish > Tested-by: Matthias > Reviewed-by: Javi Merino > Signed-off-by: Zhang Rui > Signed-off-by: Chen Yu > --- > drivers/thermal/step_wise.c | 17 +++++++++++++++-- > drivers/thermal/thermal_core.c | 19 +++++++++++++++++-- > drivers/thermal/thermal_core.h | 1 + I would prefer if you could split this patch in two. One for thermal core another one for step wise. > include/linux/thermal.h | 3 +++ > 4 files changed, 36 insertions(+), 4 deletions(-) > > diff --git a/drivers/thermal/step_wise.c b/drivers/thermal/step_wise.c > index 2f9f708..ea9366a 100644 > --- a/drivers/thermal/step_wise.c > +++ b/drivers/thermal/step_wise.c > @@ -63,6 +63,19 @@ static unsigned long get_target_state(struct thermal_instance *instance, > next_target = instance->target; > dev_dbg(&cdev->device, "cur_state=%ld\n", cur_state); > > + if (!instance->initialized) { > + if (throttle) { > + next_target = (cur_state + 1) >= instance->upper ? > + instance->upper : > + ((cur_state + 1) < instance->lower ? > + instance->lower : (cur_state + 1)); > + } else { > + next_target = THERMAL_NO_TARGET; > + } > + > + return next_target; > + } > + > switch (trend) { > case THERMAL_TREND_RAISING: > if (throttle) { > @@ -149,7 +162,7 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip) > dev_dbg(&instance->cdev->device, "old_target=%d, target=%d\n", > old_target, (int)instance->target); > > - if (old_target == instance->target) > + if (instance->initialized && old_target == instance->target) > continue; > > /* Activate a passive thermal instance */ > @@ -161,7 +174,7 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip) > instance->target == THERMAL_NO_TARGET) > update_passive_instance(tz, trip_type, -1); > > - > + instance->initialized = true; > instance->cdev->updated = false; /* cdev needs update */ > } > Considering that I understood the problem and your proposal well, I would say these changes on step wise are the perfect case for setting up a step_wise.bind_to_tz(). bind_to_tz() is already designed as an opportunity for governor to check the thermal zone status at the time of binding. Remember that moving to bind_to_tz() covers not only registration time, but governor switching too (say, user chooses user_space, then step_wise). The above code seams to be correct, but after reviewing the code of step_wise.throttle(), I would say it is already complicated and deserves simplification, when possible. > diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c > index d9e525c..682bc1e 100644 > --- a/drivers/thermal/thermal_core.c > +++ b/drivers/thermal/thermal_core.c > @@ -532,8 +532,22 @@ static void update_temperature(struct thermal_zone_device *tz) > mutex_unlock(&tz->lock); > > trace_thermal_temperature(tz); > - dev_dbg(&tz->device, "last_temperature=%d, current_temperature=%d\n", > - tz->last_temperature, tz->temperature); > + if (tz->last_temperature == THERMAL_TEMP_INVALID) > + dev_dbg(&tz->device, "last_temperature N/A, current_temperature=%d\n", > + tz->temperature); > + else > + dev_dbg(&tz->device, "last_temperature=%d, current_temperature=%d\n", > + tz->last_temperature, tz->temperature); > +} > + > +static void thermal_zone_device_reset(struct thermal_zone_device *tz) > +{ > + struct thermal_instance *pos; > + > + tz->temperature = THERMAL_TEMP_INVALID; > + tz->passive = 0; > + list_for_each_entry(pos, &tz->thermal_instances, tz_node) > + pos->initialized = false; > } > > void thermal_zone_device_update(struct thermal_zone_device *tz) > @@ -1900,6 +1914,7 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type, > > INIT_DELAYED_WORK(&(tz->poll_queue), thermal_zone_device_check); > > + thermal_zone_device_reset(tz); > thermal_zone_device_update(tz); > > return tz; > diff --git a/drivers/thermal/thermal_core.h b/drivers/thermal/thermal_core.h > index d7ac1fc..749d41a 100644 > --- a/drivers/thermal/thermal_core.h > +++ b/drivers/thermal/thermal_core.h > @@ -41,6 +41,7 @@ struct thermal_instance { > struct thermal_zone_device *tz; > struct thermal_cooling_device *cdev; > int trip; > + bool initialized; > unsigned long upper; /* Highest cooling state for this trip point */ > unsigned long lower; /* Lowest cooling state for this trip point */ > unsigned long target; /* expected cooling state */ > diff --git a/include/linux/thermal.h b/include/linux/thermal.h > index 157d366..5bcabc7 100644 > --- a/include/linux/thermal.h > +++ b/include/linux/thermal.h > @@ -43,6 +43,9 @@ > /* Default weight of a bound cooling device */ > #define THERMAL_WEIGHT_DEFAULT 0 > > +/* use value, which < 0K, to indicate an invalid/uninitialized temperature */ > +#define THERMAL_TEMP_INVALID -274000 > + > /* Unit conversion macros */ > #define KELVIN_TO_CELSIUS(t) (long)(((long)t-2732 >= 0) ? \ > ((long)t-2732+5)/10 : ((long)t-2732-5)/10) > -- > 1.8.4.2 > -- 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/