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Subject: Re: Does it make sense to create a centralized fan control module?
From: Heyi Guo <guoheyi@linux.alibaba.com>
To: openbmc@lists.ozlabs.org
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Date: Wed, 16 Jun 2021 10:02:16 +0800
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Cc: Zhikui Ren <zhikui.ren@intel.com>,
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 Vernon Mauery <vernon.mauery@linux.intel.com>, Ed Tanous <ed@tanous.net>,
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Hi All,

Any comments for my questions at the top of this thread?

Thanks,

Heyi


On 2021/6/11 上午9:23, Heyi Guo wrote:
> 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