linux-kernel - Re: [PATCH V2 0/6] PM / Domains: Implement domain performance states

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Date:   Fri, 17 Feb 2017 15:22:19 -0800
From:   Kevin Hilman <khilman@...libre.com>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Rafael Wysocki <rjw@...ysocki.net>, ulf.hansson@...aro.org,
        linaro-kernel@...ts.linaro.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Vincent Guittot <vincent.guittot@...aro.org>,
        sboyd@...eaurora.org, nm@...com, robh+dt@...nel.org,
        lina.iyer@...aro.org, rnayak@...eaurora.org
Subject: Re: [PATCH V2 0/6] PM / Domains: Implement domain performance states

Viresh Kumar <viresh.kumar@...aro.org> writes:

> An earlier series[1] tried to implement bindings for PM domain
> performance states. Rob Herring suggested that we can actually merge the
> supporting code first instead of bindings, as that will make things
> easier to understand for all. The bindings can be decided and merged
> later.
>
> The bindings [1] aren't discarded yet and this series is based on a
> version of those only. The bindings are only used by the last patch,
> which should not be applied and is only sent for completeness.
>
> IOW, this series doesn't have any dependencies and can be merged
> straight away without waiting for the DT bindings.
>
> A brief summary of the problem this series is trying to solve:
>
> Some platforms have the capability to configure the performance state of
> their Power Domains. The performance levels are represented by positive
> integer values, a lower value represents lower performance state.

And what about domains where the performance levels are represented by
someting other than positive integer values? 

IMO, this implementation should start with a more generic approach
(e.g. OPPs) that would be useful on more SoCs that just qcom.  For SoCs
like QCOM, you could use dummy/simplfied OPPs that represent the integer
values passed to the qcom firmware.

> We decided earlier that we should extend Power Domain framework to
> support active state power management as well. The power-domains until
> now were only concentrating on the idle state management of the device
> and this needs to change in order to reuse the infrastructure of power
> domains for active state management.

Yes.  Thanks for working on it!

Kevin