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To: openbmc <openbmc@lists.ozlabs.org>
From: Heyi Guo <guoheyi@linux.alibaba.com>
Subject: Does it make sense to create a centralized fan control module?
Message-ID: <f8e08249-d0e4-d632-c76b-495b8ce968d2@linux.alibaba.com>
Date: Fri, 11 Jun 2021 09:14:04 +0800
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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