From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763373AbXHKCaa (ORCPT ); Fri, 10 Aug 2007 22:30:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759254AbXHKCaV (ORCPT ); Fri, 10 Aug 2007 22:30:21 -0400 Received: from wa-out-1112.google.com ([209.85.146.178]:53356 "EHLO wa-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759133AbXHKCaU (ORCPT ); Fri, 10 Aug 2007 22:30:20 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=q1AFar0Pda6rKxsJu8j7fpOonpMHIW7eoU3WdhsCSf8GC2fA1WseZcFuLZxH/L8SgknKXCcdgZZI903g2EHzEL0VKP3GlDup3+TF18TXV7mfmfN9HsNBasjFpCliG2jbjO+ZCLH273nJRsVYFyiXZ6xBC6qmwLx+z8FzD3lmcFs= Message-ID: <4dfa50520708101930h156354c8t492677dd45e2be62@mail.gmail.com> Date: Fri, 10 Aug 2007 20:30:19 -0600 From: "David Hubbard" To: "Stefan Richter" , "Jean Delvare" , "Mark M. Hoffman" , linux-kernel@vger.kernel.org, lm-sensors@lm-sensors.org Subject: Re: [lm-sensors] 2.6.23-rc1 regression: hwmon/w83627ehf: wrong fan speed In-Reply-To: <46BCE929.5070902@s5r6.in-berlin.de> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <46B5B290.4040907@s5r6.in-berlin.de> <20070805162141.GI6221@jupiter.solarsys.private> <46B6053E.2050708@s5r6.in-berlin.de> <20070810230831.59cbc50f@hyperion.delvare> <46BCE6D0.7060300@s5r6.in-berlin.de> <46BCE929.5070902@s5r6.in-berlin.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi Stefan, (Replying to everyone on the list, sorry!) On 8/10/07, Stefan Richter wrote: > Should I hardwire correct dividers or pulse per rev in sensors.conf or > is the driver supposed to work the correct dividers out --- like it did > before 2.6.23-rc? The dividers are read-only in userspace. The driver manages the dividers automatically. The dividers are needed because the w83627ehf chip only has an 8 bit register to count pulses for each fan. So if the fan is moving slowly, you want the divider to be 128 so that every pulse gets counted. If the fan is moving fast, you want the divider to be 1 so that the register doesn't overflow. Once the register is read in by the driver, the effect of the divider is cancelled out in software so that you get an RPM reading from the fan. One side effect of this is that a fast moving fan reports the RPM more quickly than a slow moving fan. If you turn on HWMON debugging, the driver will report when it is changing the divider in dmesg. Hope that helps, David