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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Kevin Hilman <khilman@kernel.org>, Ulf Hansson <ulf.hansson@linaro.org>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Linux PM list <linux-pm@vger.kernel.org>,
        linaro-kernel <linaro-kernel@lists.linaro.org>,
        Grygorii Strashko <grygorii.strashko@ti.com>,
        Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] PM / domains: Kconfig: always enable PM_RUNTIME when genpd enabled
Date: Mon, 17 Nov 2014 02:22:52 +0100
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On Saturday, November 15, 2014 01:32:01 PM Geert Uytterhoeven wrote:
> Hi Kevin,
> 
> On Fri, Nov 14, 2014 at 6:36 PM, Kevin Hilman <khilman@kernel.org> wrote:
> >> On Thu, Nov 13, 2014 at 11:28 PM, Kevin Hilman <khilman@kernel.org> wrote:
> >>> It makes little sense to use generic power domains without runtime PM.
> >>
> >> Does it?
> >> It still powers down the PM domains on system suspend (at least on my
> >> boards ;-)
> >
> > Sure, but your devices are also using runtime PM, so I'm not sure how
> > does that change my statement above?
> 
> I do mean with CONFIG_PM_RUNTIME turned off.
> 
> If PM domain support is disabled, s2ram will not power down the PM domains.

But if PM_RUNTIME is enabled along with it, I don't think it will make much
of a different, will it?

Building the kernel with genpd and without PM_RUNTIME is possible today,
but is it really useful?  To me, it only seems to make people try to
reinvent the wheel "because PM_RUNTIME may be unset".

I have to say I'm seriously considering to make PM_SLEEP select
PM_RUNTIME too as that would make quite a few things a *lot* simpler.


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.