linux-kernel - Re: Re: Re: [PATCH 6/6] PM / devfreq: Set the min_freq and max

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Message-id: <1970403923.135851448270013777.JavaMail.weblogic@epmlwas06a>
Date:	Mon, 23 Nov 2015 09:13:34 +0000 (GMT)
From:	MyungJoo Ham <myungjoo.ham@...sung.com>
To:	Chanwoo Choi <cwchoi00@...il.com>
Cc:	박경민 <kyungmin.park@...sung.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>
Subject: Re: Re: Re: [PATCH 6/6] PM / devfreq: Set the min_freq and max_freq of
 devfreq device

> On Mon, Nov 23, 2015 at 4:21 PM, MyungJoo Ham <myungjoo.ham@...sung.com> wrote:
> > []
> >> >
> >> > The value 0 is used for min/max_freq to declare
> >> > that min/max_freq is deactivated. Therefore, it is not
> >> > required to do so; they are not intended to show the hardware
> >> > configuration as well.
> >>
> >> This case consider the devfreq device using OPP because devfreq_set_freq_table()
> >> get the number of OPP entry in OPP list before setting the min_freq/max_freq.
> >> If the devfreq device don't use the OPP entry, devfreq_set_freq_table()
> >> will return without any operation.
> >>
> >> IMHO, when devfreq device uses the OPP table including the frequency,
> >> min_freq/max_freq should show the correct value as CPUFREQ framework.
> >>
> >
> > The side effect of this patch shows up when opp_disable() and opp_enable()
> > are used.
> 
> Ah. You're right.
> I was not considering the the case of using opp_disable() and opp_enable().
> I'll consider it again including the usage case of opp_diable/opp_enable.
> 

Even without the side effect, what would be the meaning of initializing
min/max-freq to the device min/max capabilities when the users may
override it with arbitrary lower/higher values?


Cheers,
MyungJoo

ps. you will be one or two floors away from my office next week. :)