From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Date: Tue, 28 Aug 2007 11:19:42 +0000 Subject: Re: [lm-sensors] [PATCH] v1 of IBM power meter driver Message-Id: <20070828131942.18449886@hyperion.delvare> List-Id: References: <20070827211446.GG32667@tree.beaverton.ibm.com> <20070828015029.GA10107@khazad-dum.debian.net> In-Reply-To: <20070828015029.GA10107@khazad-dum.debian.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Henrique de Moraes Holschuh Cc: "Darrick J. Wong" , "Mark M. Hoffman" , linux-kernel@vger.kernel.org, lm-sensors@lm-sensors.org Hi Darrick, hi Henrique, Good thing that manufacturers start including wattmeters in their hardware. Hopefully this will help users better control their power consumption in the long run. On Mon, 27 Aug 2007 22:50:29 -0300, Henrique de Moraes Holschuh wrote: > On Mon, 27 Aug 2007, Darrick J. Wong wrote: > > documentation doesn't mention any naming conventions for sensors that > > measure Watts, so I am proposing that they be called "powerX_input" in a > > fashion similar to temperature/rpm/current sensors. If that is > > agreeable to everyone, I'll post a follow-up patch to amend the > > documentation. > > What unit should we use? Watts are way, way too big as there is no > floating/fixed point in sysfs. 10^-6 W is probably what is called for, > since we already need 10^-3 V and 10^-3 A. Small portable devices can > easily draw less than 10^-3 W nowadays. Good point. The driver currently exports non-integer values, which is not acceptable, so indeed it needs to be changed. We want at least a resolution of 10^-3 W. Not sure about 10^-6 W. I am surprised that portable devices can really draw less than 1 mW, and be it the case, I doubt that manufacturers will embed a wattmetter: it would probably draw more current than the rest of the device ;) so it may not be relevant for our decision. So I think I'd go with 10^-3 W, but I welcome diverging opinions. Out of curiosity, what is the physical resolution of IBM's device? I see that the driver relies on IPMI. Can't it be merged with the out-of-tree impisensors driver then? This would give that driver some momentum so that it can finally be merged, and I would like to avoid having two drivers if one is enough. Note though that I don't know anything about IPMI so I might as well be totally wrong ;) -- Jean Delvare _______________________________________________ lm-sensors mailing list lm-sensors@lm-sensors.org http://lists.lm-sensors.org/mailman/listinfo/lm-sensors From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759137AbXH1LTT (ORCPT ); Tue, 28 Aug 2007 07:19:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752289AbXH1LTB (ORCPT ); Tue, 28 Aug 2007 07:19:01 -0400 Received: from smtp-102-tuesday.noc.nerim.net ([62.4.17.102]:3594 "EHLO mallaury.nerim.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751396AbXH1LTB (ORCPT ); Tue, 28 Aug 2007 07:19:01 -0400 Date: Tue, 28 Aug 2007 13:19:42 +0200 From: Jean Delvare To: Henrique de Moraes Holschuh Cc: "Darrick J. Wong" , "Mark M. Hoffman" , linux-kernel@vger.kernel.org, lm-sensors@lm-sensors.org Subject: Re: [lm-sensors] [PATCH] v1 of IBM power meter driver Message-ID: <20070828131942.18449886@hyperion.delvare> In-Reply-To: <20070828015029.GA10107@khazad-dum.debian.net> References: <20070827211446.GG32667@tree.beaverton.ibm.com> <20070828015029.GA10107@khazad-dum.debian.net> X-Mailer: Sylpheed-Claws 2.5.5 (GTK+ 2.10.6; x86_64-suse-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi Darrick, hi Henrique, Good thing that manufacturers start including wattmeters in their hardware. Hopefully this will help users better control their power consumption in the long run. On Mon, 27 Aug 2007 22:50:29 -0300, Henrique de Moraes Holschuh wrote: > On Mon, 27 Aug 2007, Darrick J. Wong wrote: > > documentation doesn't mention any naming conventions for sensors that > > measure Watts, so I am proposing that they be called "powerX_input" in a > > fashion similar to temperature/rpm/current sensors. If that is > > agreeable to everyone, I'll post a follow-up patch to amend the > > documentation. > > What unit should we use? Watts are way, way too big as there is no > floating/fixed point in sysfs. 10^-6 W is probably what is called for, > since we already need 10^-3 V and 10^-3 A. Small portable devices can > easily draw less than 10^-3 W nowadays. Good point. The driver currently exports non-integer values, which is not acceptable, so indeed it needs to be changed. We want at least a resolution of 10^-3 W. Not sure about 10^-6 W. I am surprised that portable devices can really draw less than 1 mW, and be it the case, I doubt that manufacturers will embed a wattmetter: it would probably draw more current than the rest of the device ;) so it may not be relevant for our decision. So I think I'd go with 10^-3 W, but I welcome diverging opinions. Out of curiosity, what is the physical resolution of IBM's device? I see that the driver relies on IPMI. Can't it be merged with the out-of-tree impisensors driver then? This would give that driver some momentum so that it can finally be merged, and I would like to avoid having two drivers if one is enough. Note though that I don't know anything about IPMI so I might as well be totally wrong ;) -- Jean Delvare