linux-kernel - Re: [PATCH 0/2] cpufreq/opp: rework regulator initialization

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Date:   Fri, 8 Feb 2019 14:28:12 +0000
From:   Sudeep Holla <sudeep.holla@....com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Viresh Kumar <viresh.kumar@...aro.org>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        Linux Samsung SoC <linux-samsung-soc@...r.kernel.org>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Nishanth Menon <nm@...com>, Stephen Boyd <sboyd@...nel.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Dave Gerlach <d-gerlach@...com>,
        Wolfram Sang <wsa@...-dreams.de>
Subject: Re: [PATCH 0/2] cpufreq/opp: rework regulator initialization

On Fri, Feb 08, 2019 at 01:23:37PM +0100, Rafael J. Wysocki wrote:
> On Fri, Feb 8, 2019 at 1:09 PM Sudeep Holla <sudeep.holla@....com> wrote:
> >

[...]

> > Yes, in that case additional logic in the driver also needed. I am fine
> > if we enforce driver to deal with this issue, but was thinking if we can
> > make it generic. Also I was just trying to avoid adding _suspend/resume
> > to driver just to avoid this issue.
>
> I was wondering if cpufreq_offline()/online() could be invoked from
> cpufreq_suspend()/resume() for the nonboot CPUs - if the driver needs
> it (there could be a driver flag to indicate that).
>
> If they are made exit immediately when cpufreq_suspended is set (and
> the requisite driver flag is set too), that might work AFAICS.

Yes that sounds feasible. It should be fine to assume it's safe to call
cpufreq_online on a CPU even for CPU that might have failed to come
online or didn't reached a state in CPUHP from where CPUFreq callback
is executed or am I missing something ?

--
Regards,
Sudeep