linux-kernel - Re: [PATCH v4 2/7] cpufreq: Add boost frequency support in core

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Message-ID: <6633375.dICiDrHJgK@vostro.rjw.lan>
Date:	Thu, 20 Jun 2013 00:25:38 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Lukasz Majewski <l.majewski@...ess.pl>
Cc:	Dirk Brandewie <dirk.brandewie@...il.com>,
	Lukasz Majewski <l.majewski@...sung.com>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	"cpufreq@...r.kernel.org" <cpufreq@...r.kernel.org>,
	Linux PM list <linux-pm@...r.kernel.org>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Jonghwa Lee <jonghwa3.lee@...sung.com>,
	Myungjoo Ham <myungjoo.ham@...sung.com>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Andre Przywara <andre.przywara@...aro.org>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Kukjin Kim <kgene.kim@...sung.com>,
	Zhang Rui <rui.zhang@...el.com>,
	Eduardo Valentin <eduardo.valentin@...com>
Subject: Re: [PATCH v4 2/7] cpufreq: Add boost frequency support in core

On Wednesday, June 19, 2013 10:31:02 PM Lukasz Majewski wrote:
> On Wed, 19 Jun 2013 10:48:53 -0700
> Dirk Brandewie <dirk.brandewie@...il.com> wrote:
> 
> > On 06/19/2013 10:12 AM, Lukasz Majewski wrote:
> > > This commit adds boost frequency support in cpufreq core (Hardware &
> > 
> > > +/*********************************************************************
> > >    *               REGISTER / UNREGISTER CPUFREQ
> > > DRIVER                *
> > > *********************************************************************/
> > >
> > > @@ -1936,6 +2019,16 @@ int cpufreq_register_driver(struct
> > > cpufreq_driver *driver_data) cpufreq_driver = driver_data;
> > >   	write_unlock_irqrestore(&cpufreq_driver_lock, flags);
> > >
> > > +	if (!cpufreq_driver->boost_supported)
> > > +		boost.attr.mode = 0444;
> > > +
> > > +	ret = cpufreq_sysfs_create_file(&(boost.attr));
> > > +	if (ret) {
> > > +		pr_err("%s: cannot register global boost sysfs
> > > file\n",
> > > +		       __func__);
> > > +		goto err_null_driver;
> > > +	}
> > > +
> > 
> > I do not think the boost sysfs should be created at all if boost is
> > not supported.
> 
> This was my first thought. But unfortunately this "boost" attribute is
> always exported at acpi-cpufreq.c and in my opinion is part of a
> legacy API.
> 
> I totally agree with the idea of exporting boost only when supported,
> but I would like to know the community opinion about this (especially
> Viresh and Rafael shall speak up).

Simple: Export it only when supported.

Thanks,
Rafael


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