Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <20db85cb-1d16-3aad-c9b0-0a2a602f20ec@linaro.org>
Date:   Mon, 20 Jun 2022 17:17:09 +0200
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.9.1
Subject: Re: [PATCH 2/3] thermal/drivers/tegra: Remove get_trend function
Content-Language: en-US
To:     Dmitry Osipenko <digetx@gmail.com>, rafael@kernel.org
Cc:     linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
        Amit Kucheria <amitk@kernel.org>,
        Zhang Rui <rui.zhang@intel.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        "open list:TEGRA ARCHITECTURE SUPPORT" <linux-tegra@vger.kernel.org>
References: <20220616202537.303655-1-daniel.lezcano@linaro.org>
 <20220616202537.303655-2-daniel.lezcano@linaro.org>
 <6d5b2bfc-f449-668c-8c97-638eb806cb66@gmail.com>
From:   Daniel Lezcano <daniel.lezcano@linaro.org>
In-Reply-To: <6d5b2bfc-f449-668c-8c97-638eb806cb66@gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk

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@linaro.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.


-- 
<http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog