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Subject: Re: Does it make sense to create a centralized fan control module?
To: openbmc@lists.ozlabs.org
References: <f8e08249-d0e4-d632-c76b-495b8ce968d2@linux.alibaba.com>
From: Heyi Guo <guoheyi@linux.alibaba.com>
Message-ID: <3c72ee05-ec56-96ca-55da-6517307cd6a7@linux.alibaba.com>
Date: Fri, 11 Jun 2021 09:23:40 +0800
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 <openbmc-bounces+openbmc=archiver.kernel.org@lists.ozlabs.org>

Please ignore my early emails; only this one is the final version. I 
must have misused some shortcut key to send the unfinished versions 
while I wanted to save it locally...

Sorry for the noise.

Heyi

On 2021/6/11 上午9:14, Heyi Guo wrote:
> Hi All,
>
> Right now fan related data like tacho and PWM is fetched in 
> dbus-sensors, and published to d-bus as sensor data, while fan control 
> is made in another module like pid-control, which can fetch data and 
> set value via d-bus.
>
> In some common sense, we may think about putting all fan related work 
> into one single module (which may be based on pid-control), i.e. it 
> can read tacho and PWM from hardware directly, calculate the required 
> PWM by some algorithm like PID, and then write to PWM hardware 
> directly; the data will also be published to d-bus for other modules 
> to consume, like fansensor from dbus-sensors.
>
> Does it make sense to do that? Or is there any reason for the current 
> design?
>
> I'm new to OpenBMC and some of my understanding may be totally wrong.
>
> Looking forward to your expert advice.
>
> Thanks,
>
> Heyi