phosphor-pid-control: dbus tuning interface

[Patrick Venture]

On Tue, Jul 7, 2020 at 4:35 PM Jason Ling <jasonling at google.com> wrote:
>
> Apologies if this has already been discussed but..
> Would the community benefit from the addition of a dbus tuning interface for phosphor-pid-control?
>
> To get things going:
>
> initial thoughts would be to have the details of each thermal/fan PID control pushed onto dbus with loop parameters being r/w.
>
> I'm not sure about whether the output or input to the loops should be published as properties.
>
> Have this capability compiled out or runtime disabled by default
>
> Things I worry about:
>
> If the phosphor-pid-loop updates the PID output/input/error to dbus on every evaluation cycle will it bring adversely affect dbus performance or bring a system to its knees? is it better to just implement the querying of pid loop updates as a dbus method?

James and I have talked about this type of feature in the past.
Effectively making the PID control object a dbus object.  I think it
would be fine if it when it updated its own values, they weren't
broadcast - IIRC< that's an easy thing to implement, there is a
separate parameter for this.  Then it would be queryable and somewhat
tunable.  Currently the tuning is done by writing to a file, which is
how the scripts are set up - but presumably something more
programmatic or thorough could provide some value.

>
>