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Date: Fri, 26 Jul 2013 15:06:45 +0530
Message-ID: <CAKohpokK8eNid3yNGTEax_-3CZNaJ4T6Osz8RrXk11hn+Mmxxg@mail.gmail.com>
Subject: Re: [PATCH v6 2/8] cpufreq: Add boost frequency support in core
From: Viresh Kumar <viresh.kumar@linaro.org>
To: Lukasz Majewski <l.majewski@samsung.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>, Zhang Rui <rui.zhang@intel.com>,
        Eduardo Valentin <eduardo.valentin@ti.com>,
        "cpufreq@vger.kernel.org" <cpufreq@vger.kernel.org>,
        Linux PM list <linux-pm@vger.kernel.org>,
        Jonghwa Lee <jonghwa3.lee@samsung.com>,
        Lukasz Majewski <l.majewski@majess.pl>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Kukjin Kim <kgene.kim@samsung.com>,
        Myungjoo Ham <myungjoo.ham@samsung.com>, durgadoss.r@intel.com,
        Lists linaro-kernel <linaro-kernel@lists.linaro.org>
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On 26 July 2013 14:03, Lukasz Majewski <l.majewski@samsung.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.