Re: [PATCH V2 2/2] cpufreq: Change freq before suspending governors

[Rafael J. Wysocki]

On Friday, November 22, 2013 06:22:52 PM Viresh Kumar wrote:
> On 22 November 2013 18:07, Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> wrote:
> > On Friday, November 22, 2013 04:59:49 PM Viresh Kumar wrote:
> >> Some platforms might want to change frequency before suspending governors. Like:
> >> - Some platform which want to set freq to max to speed up suspend/hibernation
> >>   process.
> >> - Some platform (like: Tegra or exynos), set this to min or bootloader's
> >>   frequency.
> >>
> >> This patch adds an option for those, so that they can specify this at call to
> >> ->init(), so that cpufreq core can take care of this before suspending system.
> >>
> >> If this variable is not updated by ->init() then its value would be zero and so
> >> core wouldn't do anything.
> >>
> >> Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> >
> > I don't think this is generally necessary, because the suspend/resume routines
> > added by patch [1/2] will be executed very late during suspend or very early
> > during resume and it shouldn't really matter what performance levels the CPUs
> > are at then.
> 
> There are few things here:
> - I feel that the current place from where we have suspended stuff is not gonna
> fly. We are doing that in noirq and probably devices which might be required
> during frequency transitions might already be down.. So we *may* need to
> move that in dpm_suspend()..

That would be a much more intrusive change.  Definitely not 3.13 material
at this point.

Thanks!

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