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

[Patrick Venture]

On Fri, Jul 26, 2019 at 2:18 AM Derek Lin23 <dlin23 at lenovo.com> wrote:
>
> Hi Patrick & James:
>
>         Would you please identify when'll this feature being completed?
>         Or do you have a plan for this feature?
>
>         https://github.com/openbmc/phosphor-pid-control/issues/2

I currently don't have it on my calendar.  James, do you?

for a non-dbus-configured system, we end up using waits in the service
file for the various sensors upon which we depend to show up on dbus.
IIRC< the goal of the feature would be to no longer need that, but
rather create the dbus sensors even if nobody owns them, and just try
on read or every few reads to actually register the listening for
updates...  And just return a bad sensor reading until that happens --
but, what is a bad sensor reading, universally?

>
> Thanks,
>
> Derek
>
> -----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%.
>
> https://github.com/openbmc/entity-manager/blob/9813279b57359bd1602da236ff7d38bcc9a2fba4/configurations/R2000%20Chassis.json#L428
>
> 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>
> >
> >
> >
> >     Lenovo.com <http://www.lenovo.com/>
> >     Twitter <http://twitter.com/lenovo> | Instagram
> >     <https://instagram.com/lenovo> | Facebook
> >     <http://www.facebook.com/lenovo> | Linkedin
> >     <http://www.linkedin.com/company/lenovo> | YouTube
> >     <http://www.youtube.com/lenovovision> | Privacy
> >     <https://www.lenovo.com/gb/en/privacy-selector/>
> >
> >
> >
> >     ImageLogo-DCG-Honeycomb
> >
> >
> >