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Subject: Re: [PATCH] arm64: dts: meson: vim3: reduce cpu thermal fan trigger
 temperature
To:     Nick Xie <xieqinick@gmail.com>,
        Neil Armstrong <narmstrong@baylibre.com>
Cc:     robh+dt@kernel.org, khilman@baylibre.com, jbrunet@baylibre.com,
        martin.blumenstingl@googlemail.com, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org,
        Nick <nick@khadas.com>, artem@khadas.com
References: <20210609012849.797576-1-xieqinick@gmail.com>
 <11da3ae4-91d4-1e51-c652-e4ad518f13bd@baylibre.com>
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 <ee3341d9-350e-a84d-6836-3401be679b2a@baylibre.com>
 <CAP4nuTUt1vQjVP=3_NYaeu+m47f78ru6-MgGBiAqLeU9fJAsNg@mail.gmail.com>
From:   Daniel Lezcano <daniel.lezcano@linaro.org>
Message-ID: <09c65310-9441-9b97-d9ae-4695f0dd16af@linaro.org>
Date:   Fri, 11 Jun 2021 09:45:51 +0200
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On 11/06/2021 09:30, Nick Xie wrote:
> Hello Neil,
> 
> 
> Neil Armstrong <narmstrong@baylibre.com> 于2021年6月11日周五 下午3:15写道：
>>
>> Hi,
>>
>> On 11/06/2021 08:54, Nick Xie wrote:
>>> Hello Neil,
>>>
>>> The MCU FAN won't work until the temperature reach to 80 degree centigrade,
>>> Do you think the temperature is too high?
>>
>> I think 80 is tool high, but I fear 50 is way too low, but if you think 50 is OK after you ran some tests, just add it to the commit log and it's ok for me.
> 
> I think it is OK, we use it for a long time.

50°C sounds like normal temperature with regular load. That means the
fan will be switched on most of the time when the board is used.

And this change may be put in regard with the other trip points in the
common DT. For instance, enable the fan when reaching 80°C but set the
passive trip point to 75°C instead of 85°C.

All that depends on the hardware characteristics and TDP which are in
the TRM normally.


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