From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH 2/2] cpuidle: fix sysfs output for power_usage Date: Mon, 17 Dec 2012 13:09:48 +0100 Message-ID: <3292933.Vhp5q9ibyJ@vostro.rjw.lan> References: <1355491060-970-1-git-send-email-sivaramn@nvidia.com> <4160971.sv9ruOS3QC@vostro.rjw.lan> <20121217084607.GN10090@sivaramn-lnx> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7Bit Return-path: Received: from hydra.sisk.pl ([212.160.235.94]:36098 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752154Ab2LQMEk (ORCPT ); Mon, 17 Dec 2012 07:04:40 -0500 In-Reply-To: <20121217084607.GN10090@sivaramn-lnx> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Sivaram Nair Cc: "rafael.j.wysocki@intel.com" , "daniel.lezcano@linaro.org" , "shuox.liu@intel.com" , "akpm@linux-foundation.org" , "yanmin_zhang@intel.com" , "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" On Monday, December 17, 2012 10:46:07 AM Sivaram Nair wrote: > On Mon, Dec 17, 2012 at 08:56:45AM +0100, Rafael J. Wysocki wrote: > > On Monday, December 17, 2012 09:38:15 AM Sivaram Nair wrote: > > > On Sat, Dec 15, 2012 at 01:03:02AM +0100, Rafael J. Wysocki wrote: > > > > On Friday, December 14, 2012 03:17:37 PM Sivaram Nair wrote: > > > > > cpuidle_state->power_usage is signed; so change the corresponding sysfs > > > > > ops to output signed value instead of unsigned. > > > > > > > > What's actually wrong with printing it as an unsigned int? > > > > > > power_usage could have negative values (for example cpuidle/driver.c > > > inits this value to -1, -2 etc. when drv->power_specified is not set) and > > > these shows up badly in the sysfs output. > > > > Does "badly" mean "as big positive numbers"? > > Yes (sorry for not being clearer). > > > > > Should we actually print them at all in those case? Perhaps it'll be better to > > make the file appear empty then? > > May be, but why is power_usage signed in the first place? Please read the comment in driver.c:set_power_states() for the answer. :-) > I also noticed > Daniel Lezcano's patches that reduces the scope of this variable. So, > perhaps we can just ignore this change. OK Rafael -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.