linux-kernel - Re: [RFC][PATCH] cpufreq: User/admin documentation update and consolidation

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Date:   Mon, 20 Feb 2017 15:26:08 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:     Linux PM <linux-pm@...r.kernel.org>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Jonathan Corbet <corbet@....net>,
        Linux Documentation <linux-doc@...r.kernel.org>
Subject: Re: [RFC][PATCH] cpufreq: User/admin documentation update and
 consolidation

On 18-02-17, 02:36, Rafael J. Wysocki wrote:
> +CPU Initialization
> +==================
> +


> +Next, the scaling driver's ``->init()`` callback is invoked with the policy
> +pointer of the new CPU passed to it as the argument.  If the policy object
> +pointed to by it is new

The callbacks don't need to do anything special for a new policy.
Infact, ->init() is only called for new policies or policies which
don't have any active CPUs as of now.

> , that callback is expected to initialize the performance
> +scaling hardware interface for the given CPU (or, more precisely, for the set of
> +CPUs sharing the hardware interface it belongs to, represented by its policy
> +object) and to set parameters of the policy, like the minimum and maximum
> +frequencies supported by the hardware, the table of available frequencies (if
> +the set of supported P-states is not a continuous range), and the mask of CPUs
> +that belong to the same policy.

Maybe we should explicitly mention that both online and offline CPUs
should be set in the mask ?

> That mask is then used by the core to populate
> +the policy pointers for all of the CPUs in it.
> +
> +The next major initialization step for a new policy object is to attach a
> +scaling governor to it (to begin with, that is the default scaling governor
> +determined by the kernel configuration, but it may be changed later
> +via ``sysfs``).  First, a pointer to the new policy object is passed to the
> +governor's ``->init()`` callback which is expected to initialize all of the
> +data structures necessary to handle the given policy and, possibly, to add
> +a governor ``sysfs`` interface to it.  Next, the governor is started by
> +invoking its ``->start()`` callback.

The rest of it looked good. Nice work Rafael :)

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

-- 
viresh