From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753077AbaCGSRZ (ORCPT ); Fri, 7 Mar 2014 13:17:25 -0500 Received: from mail-pd0-f195.google.com ([209.85.192.195]:32950 "EHLO mail-pd0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751016AbaCGSRX (ORCPT ); Fri, 7 Mar 2014 13:17:23 -0500 Date: Fri, 7 Mar 2014 10:17:18 -0800 From: Guenter Roeck To: Laszlo Papp Cc: Jean Delvare , LKML , lm-sensors@lm-sensors.org Subject: Re: Tachometer speed returned rather than absolute fan speed? Message-ID: <20140307181718.GA1027@roeck-us.net> References: <20140307162524.6abd34be@endymion.delvare> <20140307163717.336873f5@endymion.delvare> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 07, 2014 at 03:47:08PM +0000, Laszlo Papp wrote: > On Fri, Mar 7, 2014 at 3:37 PM, Jean Delvare wrote: > >> > I'm quite confused. While I admit that the term "tachometer speed" is > >> > awkward, the max6650 driver is reporting fan speeds in RPM as every > >> > other hwmon driver. So I really have no idea what you think is wrong. > >> > What did you think "tachometer speed" was, if not the fan speed? Does > >> > the max6650 driver not return correct fan speeds for you? > > That is some strange behavior. If I do "echo 1 > pwm1_enable; echo 0 > > pwm1; cat fan1_input", I still see 30 for the connected fan, whereas I > can see it stopped. Is this an expected behavior? I would expect zero > as a user. > I seem to recall that I had seen that as well, with no fan connected. Maybe the tachometer registers always read at least '1'. I would think it is wrong, but we'll have to understand the chip a bit better to be able to provide a fix. Unless you already have a fix ready, of course. I'll try to re-test tonight if I find the time. Guenter