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

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Message-ID: <4433736.xh14GOaN7a@vostro.rjw.lan>
Date:	Thu, 07 Nov 2013 19:57:41 +0100
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Viresh Kumar <viresh.kumar@...aro.org>
Cc:	Xiaoguang Chen <chenxg@...vell.com>,
	"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 Thursday, November 07, 2013 10:39:38 AM Viresh Kumar wrote:
> On 7 November 2013 07:58, Xiaoguang Chen <chenxg@...vell.com> wrote:
> > When decreasing frequency, requested_freq may be less than
> > freq_target, So requested_freq minus freq_target may be negative,
> > But reqested_freq's unit is unsigned int, then the negative result
> > will be one larger interger which may be even higher than
> > requested_freq.
> >
> > This patch is to fix such issue. when result becomes negative,
> > set requested_freq as the min value of policy.
> >
> > Signed-off-by: Xiaoguang Chen <chenxg@...vell.com>
> > ---
> >  drivers/cpufreq/cpufreq_conservative.c | 7 ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> Good Catch.
> 
> Acked-by: Viresh Kumar <viresh.kumar@...aro.org>

Applied, thanks!

> We need another patch for fixing the other part of code where we
> increase freq..
> We need to replace:
> 
> if (dbs_info->requested_freq == policy->max)
>     return;
> 
> with
> 
> if (dbs_info->requested_freq >= policy->max)
>     return;
> 
> So, that we don't run unnecessary code :)

Care to prepare a patch?

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