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Subject: Re: [PATCH v1 03/10] ARM: tegra: acer-a500: Bump thermal trips by 10C
To:     Daniel Lezcano <daniel.lezcano@linaro.org>,
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        Svyatoslav Ryhel <clamor95@gmail.com>,
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From:   Dmitry Osipenko <digetx@gmail.com>
Message-ID: <53edd54a-4aa4-2100-c902-d1c8bde64a1a@gmail.com>
Date:   Tue, 15 Jun 2021 16:26:35 +0300
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15.06.2021 16:05, Daniel Lezcano пишет:
> On 15/06/2021 14:53, Dmitry Osipenko wrote:
>> 13.06.2021 21:19, Daniel Lezcano пишет:
>>> On 13/06/2021 02:25, Dmitry Osipenko wrote:
>>>
>>> [ ... ]
>>>
>>>>> You should set the trip points close to the functioning boundary
>>>>> temperature given in the hardware specification whatever the resulting
>>>>> heating effect is on the device.
>>>>>
>>>>> The thermal zone is there to protect the silicon and the system from a
>>>>> wild reboot.
>>>>>
>>>>> If the Nexus 7 is too hot after the changes, then you may act on the
>>>>> sources of the heat. For instance, set the the highest OPP to turbo or
>>>>> remove it, or, if there is one, change the thermal daemon to reduce the
>>>>> overall power consumption.
>>>>> In case you are interested in: https://lwn.net/Articles/839318/
>>>>
>>>> The DTPM is a very interesting approach. For now Tegra still misses some
>>>> basics in mainline kernel which have a higher priority, so I think it
>>>> should be good enough to perform the in-kernel thermal management for
>>>> the starter. We may consider a more complex solutions later on if will
>>>> be necessary.
>>>>
>>>> What I'm currently thinking to do is:
>>>>
>>>> 1. Set up the trips of SoC/CPU core thermal zones in accordance to the
>>>> silicon limits.
>>>>
>>>> 2. Set up the skin trips in accordance to the device limits.
>>>>
>>>> The breached skin trips will cause a mild throttling, while the SoC/CPU
>>>> trips will be allowed to cause the severe throttling. Does this sound
>>>> good to you?
>>>
>>> The skin temperature must be managed from userspace. The kernel is
>>> unable to do a smart thermal management given different thermal zones
>>> but if the goal is to go forward and prevent the tablet to be hot
>>> temporarily until the other hardware support is there, I think it is
>>> acceptable.
>>
>> The current goal is to get maximum from what we already have, thank you.
> 
> maximum of performance or maximum of mitigation ?

The best balance of both. Maximum performance + no risk of damaging
hardware + pleasant body temperature from a user perspective.