[External] Re: Questions regarding of phosphor-pid-control

Derek Lin23 dlin23 at lenovo.com
Fri Jul 26 19:18:43 AEST 2019

Hi Patrick & James:

	Would you please identify when'll this feature being completed?
	Or do you have a plan for this feature?




-----Original Message-----
From: James Feist <james.feist at linux.intel.com> 
Sent: Friday, July 19, 2019 1:57 AM
To: Derek Lin23 <dlin23 at lenovo.com>; Patrick Venture <venture at google.com>
Cc: Yonghui YH21 Liu <liuyh21 at lenovo.com>; Harry Sung1 <hsung1 at lenovo.com>; OpenBMC Maillist <openbmc at lists.ozlabs.org>; Andrew MS1 Peng <pengms1 at lenovo.com>; Lisa YJ19 Liu <liuyj19 at lenovo.com>; Haitao HT11 Wang <wanght11 at lenovo.com>; Xiaohan XH6 Xu <xuxh6 at lenovo.com>
Subject: Re: [External] Re: Questions regarding of phosphor-pid-control

On 7/17/19 7:40 PM, Derek Lin23 wrote:
> Hi Patrick:
>            The open-loop in this context is more likely to set duty of 
> PWM manually.
>            For example, when reading a sensor above or below a certain 
> pre-defined temperature, then the duty of a PWM is revved up or lower 
> to the desired fan-speed.

You could use stepwise configurations to get this response. Here's an example of a lower clipping curve that when the reading of the sensor is 20, outputs 50%, and when it reads 30 outputs 60%.


This is also configurable from the json I believe.

>            More likely, PWM is set simply by the reading of a 
> temperature sensor. A map of temperature readings and PWM values can 
> be represented as an example.
> Thank you,
> Derek
> *From:*Patrick Venture <venture at google.com>
> *Sent:* Tuesday, July 16, 2019 1:02 AM
> *To:* Derek Lin23 <dlin23 at lenovo.com>; James Feist 
> <james.feist at linux.intel.com>
> *Cc:* Yonghui YH21 Liu <liuyh21 at lenovo.com>; Harry Sung1 
> <hsung1 at lenovo.com>; OpenBMC Maillist <openbmc at lists.ozlabs.org>
> *Subject:* [External] Re: Questions regarding of phosphor-pid-control
> On Tue, Jul 9, 2019 at 2:03 AM Derek Lin23 <dlin23 at lenovo.com 
> <mailto:dlin23 at lenovo.com>> wrote:
>     Hi Patrick:
> Adding the openbmc mailing list.  Please always include this mailing 
> list in your emails for archiving and later reference as well as 
> opening up the question to others.
> Also adding James Feist as he co-maintains this codebase.
>                This is Derek from Lenovo BMC team.
>                We have some questions regarding ofphosphos-pid-control
>     <https://github.com/openbmc/phosphor-pid-control>, and we hope you
>     can provide some advice of the component.
>                Currently, we would like to import phosphor-pid-control
>     as our thermal fan control module. After a brief study, we would
>     like to know if phosphor-pid-control can support open-loop and
>     event-triggered events?
> I don't really know what open-loop means in this context.  Registering 
> for events, like?
>     Thank you for your feedbacks,
>     Derek
> ----------------------------------------------------------------------
> --
>     *Derek Lin*
>     Sr. BMC Engineer
>     8F,66, San Chong Rd., Nankang Software Park, Taipei.
>     Lenovo Taiwan
>     Phone+886281707411
>     Emaildlin23 at lenovo.com <mailto:dlin23 at lenovo.com>
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