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

Tue Jul 30 02:11:29 AEST 2019

On 7/29/19 8:30 AM, Patrick Venture wrote:
> 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?

No I don't. The dbus-configured system reloads itself when new sensors 
are discovered, and all sensors are passive.. so I'm not sure it is 
relatable.

> 
> 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>
>>>
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