linux-kernel - Re: [PATCHv2 3/3] thermal: improve hot trip handling

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Message-ID: <1458083515.4486.45.camel@intel.com>
Date:	Wed, 16 Mar 2016 00:14:35 +0000
From:	"Pandruvada, Srinivas" <srinivas.pandruvada@...el.com>
To:	"edubezval@...il.com" <edubezval@...il.com>,
	"Zhang, Rui" <rui.zhang@...el.com>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>
Subject: Re: [PATCHv2 3/3] thermal: improve hot trip handling

On Thu, 2015-12-17 at 11:13 -0800, Eduardo Valentin wrote:
> The idea is to add the choice to be notified only when temperature
> crosses trip points. The trip points affected are the non-passive
> trip points.
> 
> It will check last temperature and current temperature against
> the trip point temperature and its hysteresis.
> In case the check shows temperature has changed enought indicating
> a trip point crossing, a uevent will be sent to userspace.
> 
> The uevent contains the thermal zone type, the current temperature,
> the last temperature and the trip point in which the current
> temperature
> now resides.
> 
> The behavior of ops->notify() callback remains the same.
> 
IMO we need to handle also passive/active trips. I have some comments
here
https://patchwork.kernel.org/patch/8583171/

Thanks,
Srinivas

> Cc: Zhang Rui <rui.zhang@...el.com>
> Cc: linux-pm@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org
> Signed-off-by: Eduardo Valentin <edubezval@...il.com>
> ---
> V1->V2: none
> ---
>  drivers/thermal/thermal_core.c | 52
> ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 52 insertions(+)
> 
> diff --git a/drivers/thermal/thermal_core.c
> b/drivers/thermal/thermal_core.c
> index a229c84..e0f1f4e 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -423,6 +423,56 @@ static void handle_non_critical_trips(struct
> thermal_zone_device *tz,
>  		       def_governor->throttle(tz, trip);
>  }
>  
> +static void thermal_tripped_notify(struct thermal_zone_device *tz,
> +				   int trip, enum thermal_trip_type
> trip_type,
> +				   int trip_temp)
> +{
> +	char tuv_name[THERMAL_NAME_LENGTH + 15], tuv_temp[25],
> +		tuv_ltemp[25], tuv_trip[25], tuv_type[25];
> +	char *msg[6] = { tuv_name, tuv_temp, tuv_ltemp, tuv_trip,
> tuv_type,
> +			NULL };
> +	int upper_trip_hyst, upper_trip_temp, trip_hyst = 0;
> +	int ret = 0;
> +
> +	snprintf(tuv_name, sizeof(tuv_name), "THERMAL_ZONE=%s", tz-
> >type);
> +	snprintf(tuv_temp, sizeof(tuv_temp), "TEMP=%d", tz-
> >temperature);
> +	snprintf(tuv_ltemp, sizeof(tuv_ltemp), "LAST_TEMP=%d",
> +		 tz->last_temperature);
> +	snprintf(tuv_trip, sizeof(tuv_trip), "TRIP=%d", trip);
> +	snprintf(tuv_type, sizeof(tuv_type), "TRIP_TYPE=%d",
> trip_type);
> +
> +	mutex_lock(&tz->lock);
> +
> +	/* crossing up */
> +	if (tz->last_temperature < trip_temp && trip_temp < tz-
> >temperature)
> +		kobject_uevent_env(&tz->device.kobj, KOBJ_CHANGE,
> msg);
> +
> +	if (tz->ops->get_trip_hyst)
> +		tz->ops->get_trip_hyst(tz, trip, &trip_hyst);
> +
> +	/* crossing down, check for hyst */
> +	trip_temp -= trip_hyst;
> +	if (tz->last_temperature > trip_temp && trip_temp > tz-
> >temperature) {
> +		snprintf(tuv_trip, sizeof(tuv_trip), "TRIP=%d", trip
> - 1);
> +		kobject_uevent_env(&tz->device.kobj, KOBJ_CHANGE,
> msg);
> +	}
> +
> +	ret = tz->ops->get_trip_temp(tz, trip + 1,
> &upper_trip_temp);
> +	if (ret)
> +		goto unlock;
> +
> +	if (tz->ops->get_trip_hyst)
> +		tz->ops->get_trip_hyst(tz, trip + 1,
> &upper_trip_hyst);
> +
> +	upper_trip_temp -= upper_trip_hyst;
> +	if (tz->last_temperature > upper_trip_temp &&
> +	    upper_trip_temp > tz->temperature)
> +		kobject_uevent_env(&tz->device.kobj, KOBJ_CHANGE,
> msg);
> +
> +unlock:
> +	mutex_unlock(&tz->lock);
> +}
> +
>  static void handle_critical_trips(struct thermal_zone_device *tz,
>  				int trip, enum thermal_trip_type
> trip_type)
>  {
> @@ -430,6 +480,8 @@ static void handle_critical_trips(struct
> thermal_zone_device *tz,
>  
>  	tz->ops->get_trip_temp(tz, trip, &trip_temp);
>  
> +	thermal_tripped_notify(tz, trip, trip_type, trip_temp);
> +
>  	/* If we have not crossed the trip_temp, we do not care. */
>  	if (trip_temp <= 0 || tz->temperature < trip_temp)
>  		return;