linux-kernel - Re: [PATCH] cpufreq: conservative: fix requested

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Date:	Mon, 11 Nov 2013 10:13:26 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	Stratos Karafotis <skarafotis@...il.com>
Cc:	Xiaoguang Chen <chenxg@...vell.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	"cpufreq@...r.kernel.org" <cpufreq@...r.kernel.org>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Xiaoguang Chen <chenxg.marvell@...il.com>
Subject: Re: [PATCH] cpufreq: conservative: fix requested_freq reduction issue

On 9 November 2013 00:59, Stratos Karafotis <skarafotis@...il.com> wrote:
> I removed the check you proposed in this commit 934dac1ea072 to avoid
> the duplicate check in cs_check_cpu and in dbs_cpufreq_notifier.
>
> I agree that we don't need dbs_cpufreq_notifier if we transfer checks in
> cs_check_cpu. But I'm not 100% sure if the notifier also covers
> other cases and if it can be safely removed.

It is there to take care of out-of-sync issues, and was introduced by this
commit, so probably it will stay as is:

commit a8d7c3bc2396aff14f9e920677072cb55b016040
Author: Elias Oltmanns <eo@...ensachen.de>
Date:   Mon Oct 22 09:50:13 2007 +0200

    [CPUFREQ] Make cpufreq_conservative handle out-of-sync events properly

    Make cpufreq_conservative handle out-of-sync events properly

    Currently, the cpufreq_conservative governor doesn't get notified when the
    actual frequency the cpu is running at differs from what cpufreq thought it
    was. As a result the cpu may stay at the maximum frequency after a s2ram /
    resume cycle even though the system is idle.

    Signed-off-by: Elias Oltmanns <eo@...ensachen.de>
    Signed-off-by: Dave Jones <davej@...hat.com>
---
 drivers/cpufreq/cpufreq_conservative.c | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)
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