linux-kernel - Re: [PATCH v2 1/3] cpufreq:boost: CPU frequency boost code unification for software and hardware solutions

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Date:	Wed, 12 Jun 2013 13:40:23 +0200
From:	Lukasz Majewski <l.majewski@...sung.com>
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	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>,
	Lukasz Majewski <l.majewski@...ess.pl>,
	Andre Przywara <andre.przywara@...aro.org>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Kukjin Kim <kgene.kim@...sung.com>
Subject: Re: [PATCH v2 1/3] cpufreq:boost: CPU frequency boost code unification
 for software and hardware solutions

On Wed, 12 Jun 2013 13:23:20 +0200, Rafael J. Wysocki wrote:

Hi Rafael,

> On Wednesday, June 12, 2013 09:39:38 AM Lukasz Majewski wrote:
> > Hi Viresh,
> > 
> > > Hi,
> > > 
> > > Change subject to: "cpufreq: Add boost frequency support in core"
> > 
> > Ok.
> > 
> > > 
> > > On 11 June 2013 14:33, Lukasz Majewski <l.majewski@...sung.com>
> > > wrote:
> > > > This commit adds support for software based frequency boosting.
> > > 
> > > No. It adds support for both software and hardware boosting. So
> > > just write: This commit adds boost frequency support in cpufreq
> > > core (Hardware & Software).
> > 
> > Ok.
> > > 
> > > > Some SoC (like Exynos4 - e.g. 4x12) allow setting frequency
> > > > above its normal condition limits. Such a change shall be only
> > > > done for a short
> > > 
> > > s/condition/operation
> > > s/change/mode
> > > s/done/used
> > > 
> > 
> > Ok.
> > 
> > > > time.
> > > >
> > > > Overclocking (boost) support is essentially provided by platform
> > > > dependent cpufreq driver.
> > > >
> > > > This commit unifies support for SW and HW (Intel) over clocking
> > > > solutions in the core cpufreq driver. Previously the "boost"
> > > > sysfs attribute was defined at acpi driver code.
> > > > By default boost is disabled. One global attribute is available
> > > > at: /sys/devices/system/cpu/cpufreq/boost.
> > > 
> > > Enter a blank line here.
> > 
> > Ok
> > 
> > > 
> > > > It only shows up when cpufreq driver supports overclocking.
> > > > Under the hood frequencies dedicated for boosting are marked
> > > > with a special flag (CPUFREQ_BOOST_FREQ) at driver's frequency
> > > > table. It is the user's concern to enable/disable overclocking
> > > > with proper call to sysfs.
> > > 
> > > Good.
> > > 
> > > > Signed-off-by: Lukasz Majewski <l.majewski@...sung.com>
> > > > Signed-off-by: Myungjoo Ham <myungjoo.ham@...sung.com>
> > > >
> > > > --- 
> >     ^^^^
> > [*] this --- was added manually by me.
> > 
> > > > Changes for v2:
> > > > - Removal of cpufreq_boost structure and move its fields to
> > > > cpufreq_driver structure
> > > > - Flag to indicate if global boost attribute is already defined
> > > > - Extent the pr_{err|debbug} functions to show current function
> > > > names ---
> > > 
> > > You don't have to manually add "---" here. Just keep a blank line
> > > instead.
> > 
> > One "---" is added by git automatically. The [*] was added to
> > distinct the changelog from rest of the commit. At least older
> > versions of GIT required this to not include changelog to commit
> > messages.
> 
> Which doesn't matter anyway.  None of them will show up in git log,
> so don't worry. :-)

:-)

> 
> [...]
> 
> > 
> > > And so we must have used
> > > boost_en here.
> > 
> > boost_en has two meanings:
> > 0 - either boost disabled or not supported (when
> > low_level_boost=NULL). 1 - boost is enabled.
> 
> Gosh, please don't do that.  Use *two* flags, one meaning "supported"
> and the second meaning "enabled".

That was already pointed out by Viresh. I will stick to his
guidelines :-).

> 
> Thanks,
> Rafael
> 
> 



-- 
Best regards,

Lukasz Majewski

Samsung R&D Institute Poland (SRPOL) | Linux Platform Group
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