From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: Robin Murphy <robin.murphy@arm.com>,
Peter Geis <pgwipeout@gmail.com>,
Rob Herring <robh+dt@kernel.org>,
Heiko Stuebner <heiko@sntech.de>
Cc: devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] arm64: dts: rockchip: add thermal fan control to rockpro64
Date: Fri, 13 Aug 2021 16:54:42 +0200 [thread overview]
Message-ID: <2b1050f2-0311-1871-820a-f876218894bc@linaro.org> (raw)
In-Reply-To: <893701da-ea17-00ab-5e31-c745051ac9b9@arm.com>
Hi Robin,
On 13/08/2021 15:51, Robin Murphy wrote:
> On 2021-08-13 13:59, Daniel Lezcano wrote:
>> On 30/07/2021 17:17, Peter Geis wrote:
>>> The rockpro64 had a fan node since
>>> commit 5882d65c1691 ("arm64: dts: rockchip: Add PWM fan for RockPro64")
>>> however it was never tied into the thermal driver for automatic control.
>>>
>>> Add the links to the thermal node to permit the kernel to handle this
>>> automatically.
>>> Borrowed from the (rk3399-khadas-edge.dtsi).
>>>
>>> Signed-off-by: Peter Geis <pgwipeout@gmail.com>
[ ... ]
>>> +&cpu_thermal {
>>> + trips {
>>> + cpu_warm: cpu_warm {
>>> + temperature = <55000>;
>>> + hysteresis = <2000>;
>>> + type = "active";
>>> + };
>>> +
>>> + cpu_hot: cpu_hot {
>>> + temperature = <65000>;
>>> + hysteresis = <2000>;
>>> + type = "active";
>>> + };
>>> + };
>>> +
>>
>> Why two trip points ?
>>
>> Why not one functioning temperature and no lower / upper limits for the
>> cooling maps ?
>
> Certainly when I first did this for NanoPC-T4, IIRC it was to avoid the
> fan ramping up too eagerly, since level 1 for my fan is effectively
> silent but still cools enough to let a moderate load eventually settle
> to a steady state below the second trip.
Thanks for your answer.
What would be the governor for this setup ?
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next prev parent reply other threads:[~2021-08-13 14:54 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-30 15:17 [PATCH v3] arm64: dts: rockchip: add thermal fan control to rockpro64 Peter Geis
2021-08-13 8:51 ` Heiko Stuebner
2021-08-13 12:59 ` Daniel Lezcano
2021-08-13 13:51 ` Robin Murphy
2021-08-13 14:54 ` Daniel Lezcano [this message]
2021-08-13 15:10 ` Peter Geis
2021-08-13 15:46 ` Daniel Lezcano
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