linux-kernel - Re: [PATCH] Cpufreq: Change sysfs interface cpuinfo_cur

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Message-ID: <52933AB5.9060409@intel.com>
Date:	Mon, 25 Nov 2013 19:55:33 +0800
From:	Lan Tianyu <tianyu.lan@...el.com>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
CC:	Viresh Kumar <viresh.kumar@...aro.org>, hg197@....de,
	"cpufreq@...r.kernel.org" <cpufreq@...r.kernel.org>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] Cpufreq: Change sysfs interface cpuinfo_cur_freq access
 privilege

On 11/25/2013 07:26 PM, Rafael J. Wysocki wrote:
> On Monday, November 25, 2013 01:33:39 PM Lan Tianyu wrote:
>> On 2013年11月25日 12:30, Viresh Kumar wrote:
>>> On 25 November 2013 08:23, Lan Tianyu <tianyu.lan@...el.com> wrote:
>>>> Currently, cpuinfo_cur_freq is only accessible for root user while
>>>> other cpufreq sysfs interfaces(E,G scaling_cur_freq) are available
>>>> to ordinary user. This seems make no sense. This patch is to change
>>>> it.
>>>
>>> There is nothing wrong with the code and so this is more of a design
>>> change..
>>>
>>> Probably Rafael can help us here as cpufreq_cur_freq will read stuff
>>> directly from hardware instead of using cached value in software.
>>
>> I think so, too. I also tried to checking the reason of the privilege by
>> git log but the code was there before linux kernel being migrated to git
>> repository.
>
> And it has always behaved in the same way?  Then I wouldn't change it.
>

It has been there since 2.6.12-rc2 or more early. But the 
cpuinfo_cur_freq is read-only and seems no harmful.

Request from bug 65611.
https://bugzilla.kernel.org/show_bug.cgi?id=65611.


> Thanks!
>


-- 
Best Regards
Tianyu Lan
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