linux-kernel - Re: [PATCH] thermal/core: Clear all mitigation when thermal zone is disabled

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Message-ID: <YcSNIJVnCQvx6ttg@google.com>
Date:   Thu, 23 Dec 2021 06:52:16 -0800
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Manaf Meethalavalappu Pallikunhi <quic_manafm@...cinc.com>
Cc:     "Rafael J . Wysocki" <rafael@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Amit Kucheria <amitk@...nel.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Thara Gopinath <thara.gopinath@...aro.org>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] thermal/core: Clear all mitigation when thermal zone is
 disabled

On Tue, Dec 21, 2021 at 04:11:58PM +0530, Manaf Meethalavalappu Pallikunhi wrote:
> Whenever a thermal zone is in trip violated state, there is a chance
> that the same thermal zone mode can be disabled either via thermal
> core API or via thermal zone sysfs. Once it is disabled, the framework
> bails out any re-evaluation of thermal zone. It leads to a case where
> if it is already in mitigation state, it will stay the same state
> until it is re-enabled.
> 
> To avoid above mentioned issue, on thermal zone disable request
> reset thermal zone and clear mitigation for each trip explicitly.
> 
> Signed-off-by: Manaf Meethalavalappu Pallikunhi <quic_manafm@...cinc.com>
> ---
>  drivers/thermal/thermal_core.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 51374f4..a8ae340 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -427,6 +427,7 @@ static int thermal_zone_device_set_mode(struct thermal_zone_device *tz,
>  					enum thermal_device_mode mode)
>  {
>  	int ret = 0;
> +	int count;
>  
>  	mutex_lock(&tz->lock);
>  
> @@ -449,8 +450,14 @@ static int thermal_zone_device_set_mode(struct thermal_zone_device *tz,
>  
>  	if (mode == THERMAL_DEVICE_ENABLED)
>  		thermal_notify_tz_enable(tz->id);
> -	else
> +	else {
> +		/* make sure all previous throttlings are cleared */
> +		thermal_zone_device_init(tz);
> +		for (count = 0; count < tz->trips; count++)
> +			handle_thermal_trip(tz, count);

nit: s/count/trip/