Re: [PATCH 1/2] thermal: cooling: Check Energy Model type in cpufreq_cooling and devfreq_cooling

From: Doug Anderson
Date: Wed Feb 16 2022 - 12:21:40 EST


Hi,

On Tue, Feb 8, 2022 at 1:32 AM Lukasz Luba <lukasz.luba@xxxxxxx> wrote:
>
> > Another important thing is the consistent scale of the power values
> > provided by the cooling devices. All of the cooling devices in a single
> > thermal zone should have power values reported either in milli-Watts
> > or scaled to the same 'abstract scale'.
>
> This can change. We have removed the userspace governor from kernel
> recently. The trend is to implement thermal policy in FW. Dealing with
> some intermediate configurations are causing complicated design, support
> of the algorithm logic is also more complex.

One thing that didn't get addressed is the whole "The trend is to
implement thermal policy in FW". I'm not sure I can get on board with
that trend. IMO "moving to FW" isn't a super great trend. FW is harder
to update than kernel and trying to keep it in sync with the kernel
isn't wonderful. Unless something _has_ to be in FW I personally
prefer it to be in the kernel.

...although now that I re-read this, I'm not sure which firmware you
might be talking about. Is this the AP firmware, or some companion
chip / coprocessor? Even so, I'd still rather see things done in the
kernel when possible...

-Doug