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From: rjw@sisk.pl (Rafael J. Wysocki)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] cpufreq: exynos5440: Fix to skip when new frequency same as current
Date: Thu, 08 Aug 2013 01:25:08 +0200	[thread overview]
Message-ID: <2331427.ybQdfvflPh@vostro.rjw.lan> (raw)
In-Reply-To: <CAKohpom0gPk9BXRP2eEuX_HBXDut=wynrZfvOH1tcEQY6CMLNQ@mail.gmail.com>

On Wednesday, August 07, 2013 05:03:59 PM Viresh Kumar wrote:
> On 7 August 2013 17:00, Sudeep KarkadaNagesha
> <Sudeep.KarkadaNagesha@arm.com> wrote:
> > Any particular reason we need this check in all drivers after your
> > commit: 5a1c0228 "cpufreq: Avoid calling cpufreq driver's target()
> > routine if target_freq == policy->cur"
> >
> > I think it can removed from all drivers, am I missing something ?
> 
> Yeah.. Just a bit though :)
> 
> So, cpufreq core checks this when we call target for any frequency.
> Now, cpufreq driver actually does a cpufreq_frequency_table_target()
> and so the frequency may vary than what is requested, in case
> requested frequency isn't picked from the table.
> 
> In such cases we check it again to be sure that we aren't at this
> frequency already..
> 
> Earlier I thought of calling cpufreq_frequency_table_target() in the
> core before calling target but dropped the idea as I wasn't sure of
> the side effects.
> 
> @Rafael: Do you see why we shouldn't/can't call
> cpufreq_frequency_table_target() from the core itself and so drivers
> never need to do it?

It looks like it would require us to redefine .target() to take next_state
instead of target_freq (at least in the acpi-cpufreq case), wouldn't it?

Rafael

  reply	other threads:[~2013-08-07 23:25 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-07 11:16 [PATCH] cpufreq: exynos5440: Fix to skip when new frequency same as current Amit Daniel Kachhap
2013-08-07 11:22 ` Viresh Kumar
2013-08-07 11:30   ` Sudeep KarkadaNagesha
2013-08-07 11:33     ` Viresh Kumar
2013-08-07 23:25       ` Rafael J. Wysocki [this message]
2013-08-08  2:33         ` Viresh Kumar

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