linux-kernel - Re: [PATCH v6 2/8] cpufreq: Add boost frequency support in core

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Message-ID: <CAKohpokK8eNid3yNGTEax_-3CZNaJ4T6Osz8RrXk11hn+Mmxxg@mail.gmail.com>
Date:	Fri, 26 Jul 2013 15:06:45 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	Lukasz Majewski <l.majewski@...sung.com>
Cc:	"Rafael J. Wysocki" <rjw@...k.pl>, Zhang Rui <rui.zhang@...el.com>,
	Eduardo Valentin <eduardo.valentin@...com>,
	"cpufreq@...r.kernel.org" <cpufreq@...r.kernel.org>,
	Linux PM list <linux-pm@...r.kernel.org>,
	Jonghwa Lee <jonghwa3.lee@...sung.com>,
	Lukasz Majewski <l.majewski@...ess.pl>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Kukjin Kim <kgene.kim@...sung.com>,
	Myungjoo Ham <myungjoo.ham@...sung.com>, durgadoss.r@...el.com,
	Lists linaro-kernel <linaro-kernel@...ts.linaro.org>
Subject: Re: [PATCH v6 2/8] cpufreq: Add boost frequency support in core

On 26 July 2013 14:03, Lukasz Majewski <l.majewski@...sung.com> wrote:
> The problem here is with the cpufreq_driver->set_boost() call.
>
> I tried to avoid acquiring lock at one function and release it at
> another (in this case cpufreq_boost_set_sw), especially since the
> __cpufreq_governor() acquires its own lock - good place for deadlock.
>
> Is it OK for you to grab lock at one function
> (cpufreq_boost_trigger_state()) and then at other function
> (cpufreq_boost_set_sw) release it before calling __cpufreq_governor()
> and grab it again after its completion?

Problem is not only that.. but we shouldn't call boost_set() of drivers
like acpi-cpufreq with this lock..... Leave it as it is for now.. Let me see
if I can think of any problems that can happen due to this.
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