linux-kernel - Re: [PATCH v3 4/6] thermal: core: Send trip crossing notifications at init time if needed

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Date: Thu, 4 Apr 2024 23:55:30 +0100
From: Lukasz Luba <lukasz.luba@....com>
To: "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc: LKML <linux-kernel@...r.kernel.org>, Linux PM <linux-pm@...r.kernel.org>,
 Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
 Daniel Lezcano <daniel.lezcano@...aro.org>,
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
Subject: Re: [PATCH v3 4/6] thermal: core: Send trip crossing notifications at
 init time if needed



On 4/2/24 20:02, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> If a trip point is already exceeded by the zone temperature at the
> initialization time, no trip crossing notification is send regarding
> this even though mitigation should be started then.
> 
> Address this by rearranging the code in handle_thermal_trip() to
> send a trip crossing notification for trip points already exceeded
> by the zone temperature initially which also allows to reduce its
> size by using the observation that the initialization and regular
> trip crossing on the way up become the same case then.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
> 
> v2 -> v3: New patch
> 
> ---
>   drivers/thermal/thermal_core.c |   37 ++++++++++++++++---------------------
>   1 file changed, 16 insertions(+), 21 deletions(-)
> 
> Index: linux-pm/drivers/thermal/thermal_core.c
> ===================================================================
> --- linux-pm.orig/drivers/thermal/thermal_core.c
> +++ linux-pm/drivers/thermal/thermal_core.c
> @@ -364,6 +364,7 @@ static void handle_thermal_trip(struct t
>   				struct thermal_trip_desc *td)
>   {
>   	const struct thermal_trip *trip = &td->trip;
> +	int old_threshold;
>   
>   	if (trip->temperature == THERMAL_TEMP_INVALID)
>   		return;
> @@ -375,25 +376,11 @@ static void handle_thermal_trip(struct t
>   	 * is what needs to be compared with the previous zone temperature
>   	 * to decide which action to take.
>   	 */
> -	if (tz->last_temperature == THERMAL_TEMP_INVALID) {
> -		/* Initialization. */
> -		td->threshold = trip->temperature;
> -		if (tz->temperature >= td->threshold)
> -			td->threshold -= trip->hysteresis;
> -	} else if (tz->last_temperature < td->threshold) {
> -		/*
> -		 * There is no mitigation under way, so it needs to be started
> -		 * if the zone temperature exceeds the trip one.  The new
> -		 * threshold is then set to the low temperature of the trip.
> -		 */
> -		if (tz->temperature >= trip->temperature) {
> -			thermal_notify_tz_trip_up(tz, trip);
> -			thermal_debug_tz_trip_up(tz, trip);
> -			td->threshold = trip->temperature - trip->hysteresis;
> -		} else {
> -			td->threshold = trip->temperature;
> -		}
> -	} else {
> +	old_threshold = td->threshold;
> +	td->threshold = trip->temperature;
> +
> +	if (tz->last_temperature >= old_threshold &&
> +	    tz->last_temperature != THERMAL_TEMP_INVALID) {
>   		/*
>   		 * Mitigation is under way, so it needs to stop if the zone
>   		 * temperature falls below the low temperature of the trip.
> @@ -402,10 +389,18 @@ static void handle_thermal_trip(struct t
>   		if (tz->temperature < trip->temperature - trip->hysteresis) {
>   			thermal_notify_tz_trip_down(tz, trip);
>   			thermal_debug_tz_trip_down(tz, trip);
> -			td->threshold = trip->temperature;
>   		} else {
> -			td->threshold = trip->temperature - trip->hysteresis;
> +			td->threshold -= trip->hysteresis;
>   		}
> +	} else if (tz->temperature >= trip->temperature) {
> +		/*
> +		 * There is no mitigation under way, so it needs to be started
> +		 * if the zone temperature exceeds the trip one.  The new
> +		 * threshold is then set to the low temperature of the trip.
> +		 */
> +		thermal_notify_tz_trip_up(tz, trip);
> +		thermal_debug_tz_trip_up(tz, trip);
> +		td->threshold -= trip->hysteresis;
>   	}
>   
>   	if (trip->type == THERMAL_TRIP_CRITICAL || trip->type == THERMAL_TRIP_HOT)
> 
> 
> 


Reviewed-by: Lukasz Luba <lukasz.luba@....com>