linux-kernel - Re: [PATCH 2/3] thermal/drivers/tegra: Remove get

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Date:   Mon, 20 Jun 2022 17:17:09 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Dmitry Osipenko <digetx@...il.com>, rafael@...nel.org
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        Amit Kucheria <amitk@...nel.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        "open list:TEGRA ARCHITECTURE SUPPORT" <linux-tegra@...r.kernel.org>
Subject: Re: [PATCH 2/3] thermal/drivers/tegra: Remove get_trend function

On 18/06/2022 14:44, Dmitry Osipenko wrote:
> 16.06.2022 23:25, Daniel Lezcano пишет:
>> The get_trend function does already what the generic framework does.
>>
>> Remove it.
>>
>> Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
>> ---

[ ... ]

>>   static void thermal_irq_enable(struct tegra_thermctl_zone *zn)
>>   {
>>   	u32 r;
>> @@ -716,7 +685,6 @@ static int tegra_thermctl_set_trips(void *data, int lo, int hi)
>>   static const struct thermal_zone_of_device_ops tegra_of_thermal_ops = {
>>   	.get_temp = tegra_thermctl_get_temp,
>>   	.set_trip_temp = tegra_thermctl_set_trip_temp,
>> -	.get_trend = tegra_thermctl_get_trend,
>>   	.set_trips = tegra_thermctl_set_trips,
>>   };
>>   
> 
> The framework doesn't use the trip temperature, is it really the same?
> Previously, if temperature was above the trip and was dropping, then it
> was THERMAL_TREND_STABLE instead of THERMAL_TREND_DROPPING.

Actually, the only difference is the temp > trip and the temperature < 
last_temperature. It results in the STABLE trend and the governor does 
nothing.

With the core trend function for the same inputs, temperature < 
last_temperature results in a DROPPING but as temp > trip the 'throttle' 
boolean is true in the governor, and get_next_state() with DROPPING + 
throttle=true, results in nothing because the action happens when 
throttle=false.

All the combinations result at end at the same action from the governor.



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