linux-kernel - Re: [RFC PATCH 4/4] thermal: Modify thermal governors to do nothing for "cold" trip points

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Date:   Wed, 15 Jul 2020 16:35:39 +0800
From:   Zhang Rui <rui.zhang@...el.com>
To:     Thara Gopinath <thara.gopinath@...aro.org>,
        daniel.lezcano@...aro.org, robh+dt@...nel.org
Cc:     linux-pm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 4/4] thermal: Modify thermal governors to do nothing
 for "cold" trip points

On Fri, 2020-07-10 at 09:51 -0400, Thara Gopinath wrote:
> For now, thermal governors do not support monitoring of falling
> temperature. Hence, in case of calls to the governor for trip points
> marked
> as cold, return doing nothing.
> 
> Signed-off-by: Thara Gopinath <thara.gopinath@...aro.org>
> ---
>  drivers/thermal/gov_bang_bang.c       | 8 ++++++++
>  drivers/thermal/gov_fair_share.c      | 8 ++++++++
>  drivers/thermal/gov_power_allocator.c | 8 ++++++++
>  drivers/thermal/gov_step_wise.c       | 8 ++++++++
>  4 files changed, 32 insertions(+)

userspace governor does not support cold trip point neither.

So how about adding the check in handle_non_critical_trips first, and
remove the check later, after all the governors support cold trip?

thanks,
rui
> 
> diff --git a/drivers/thermal/gov_bang_bang.c
> b/drivers/thermal/gov_bang_bang.c
> index 991a1c54296d..8324d13de1e7 100644
> --- a/drivers/thermal/gov_bang_bang.c
> +++ b/drivers/thermal/gov_bang_bang.c
> @@ -99,6 +99,14 @@ static void thermal_zone_trip_update(struct
> thermal_zone_device *tz, int trip)
>  static int bang_bang_control(struct thermal_zone_device *tz, int
> trip)
>  {
>  	struct thermal_instance *instance;
> +	enum thermal_trip_type trip_type;
> +
> +	/* Return doing nothing in case of cold trip point */
> +	if (trip != THERMAL_TRIPS_NONE) {
> +		tz->ops->get_trip_type(tz, trip, &trip_type);
> +		if (trip_type == THERMAL_TRIP_COLD)
> +			return 0;
> +	}
>  
>  	thermal_zone_trip_update(tz, trip);
>  
> diff --git a/drivers/thermal/gov_fair_share.c
> b/drivers/thermal/gov_fair_share.c
> index aaa07180ab48..c0adce525faa 100644
> --- a/drivers/thermal/gov_fair_share.c
> +++ b/drivers/thermal/gov_fair_share.c
> @@ -81,6 +81,14 @@ static int fair_share_throttle(struct
> thermal_zone_device *tz, int trip)
>  	int total_weight = 0;
>  	int total_instance = 0;
>  	int cur_trip_level = get_trip_level(tz);
> +	enum thermal_trip_type trip_type;
> +
> +	/* Return doing nothing in case of cold trip point */
> +	if (trip != THERMAL_TRIPS_NONE) {
> +		tz->ops->get_trip_type(tz, trip, &trip_type);
> +		if (trip_type == THERMAL_TRIP_COLD)
> +			return 0;
> +	}
>  
>  	list_for_each_entry(instance, &tz->thermal_instances, tz_node)
> {
>  		if (instance->trip != trip)
> diff --git a/drivers/thermal/gov_power_allocator.c
> b/drivers/thermal/gov_power_allocator.c
> index 44636475b2a3..2644ad4d4032 100644
> --- a/drivers/thermal/gov_power_allocator.c
> +++ b/drivers/thermal/gov_power_allocator.c
> @@ -613,8 +613,16 @@ static int power_allocator_throttle(struct
> thermal_zone_device *tz, int trip)
>  {
>  	int ret;
>  	int switch_on_temp, control_temp;
> +	enum thermal_trip_type trip_type;
>  	struct power_allocator_params *params = tz->governor_data;
>  
> +	/* Return doing nothing in case of cold trip point */
> +	if (trip != THERMAL_TRIPS_NONE) {
> +		tz->ops->get_trip_type(tz, trip, &trip_type);
> +		if (trip_type == THERMAL_TRIP_COLD)
> +			return 0;
> +	}
> +
>  	/*
>  	 * We get called for every trip point but we only need to do
>  	 * our calculations once
> diff --git a/drivers/thermal/gov_step_wise.c
> b/drivers/thermal/gov_step_wise.c
> index 2ae7198d3067..009aefda0441 100644
> --- a/drivers/thermal/gov_step_wise.c
> +++ b/drivers/thermal/gov_step_wise.c
> @@ -186,6 +186,14 @@ static void thermal_zone_trip_update(struct
> thermal_zone_device *tz, int trip)
>  static int step_wise_throttle(struct thermal_zone_device *tz, int
> trip)
>  {
>  	struct thermal_instance *instance;
> +	enum thermal_trip_type trip_type;
> +
> +	/* For now, return doing nothing in case of cold trip point */
> +	if (trip != THERMAL_TRIPS_NONE) {
> +		tz->ops->get_trip_type(tz, trip, &trip_type);
> +		if (trip_type == THERMAL_TRIP_COLD)
> +			return 0;
> +	}
>  
>  	thermal_zone_trip_update(tz, trip);
>