From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753592Ab3KYMCL (ORCPT ); Mon, 25 Nov 2013 07:02:11 -0500 Received: from v094114.home.net.pl ([79.96.170.134]:63004 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753248Ab3KYMCI convert rfc822-to-8bit (ORCPT ); Mon, 25 Nov 2013 07:02:08 -0500 From: "Rafael J. Wysocki" To: Lan Tianyu Cc: Viresh Kumar , hg197@gmx.de, "cpufreq@vger.kernel.org" , "linux-pm@vger.kernel.org" , Linux Kernel Mailing List Subject: Re: [PATCH] Cpufreq: Change sysfs interface cpuinfo_cur_freq access privilege Date: Mon, 25 Nov 2013 13:14:54 +0100 Message-ID: <1521595.q8BSAikk1K@vostro.rjw.lan> User-Agent: KMail/4.10.5 (Linux/3.12.0-rc6+; KDE/4.10.5; x86_64; ; ) In-Reply-To: <52933AB5.9060409@intel.com> References: <1385348018-30525-1-git-send-email-tianyu.lan@intel.com> <5074010.ha99UACE9S@vostro.rjw.lan> <52933AB5.9060409@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday, November 25, 2013 07:55:33 PM Lan Tianyu wrote: > 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 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. If it reads things directly from hardware, it may not be totally neutral. Thanks! -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.