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

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Message-ID: <CAKohpo=2xjR=nr5hyMg9bve5_uVbV79R2FTxks0bLmL7kNV9Mg@mail.gmail.com>
Date:	Thu, 7 Nov 2013 10:39:38 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	Xiaoguang Chen <chenxg@...vell.com>
Cc:	"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 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>

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 :)
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