From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lucas Levrel Subject: Re: Customizing fan behaviour (temperatures) Date: Wed, 13 Jul 2016 22:16:57 +0200 (CEST) Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from smtpfb2-g21.free.fr ([212.27.42.10]:49801 "EHLO smtpfb2-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750829AbcGMUXw (ORCPT ); Wed, 13 Jul 2016 16:23:52 -0400 Received: from smtp6-g21.free.fr (smtp6-g21.free.fr [212.27.42.6]) by smtpfb2-g21.free.fr (Postfix) with ESMTP id 60DAACAA0BE for ; Wed, 13 Jul 2016 22:17:01 +0200 (CEST) Received: from [192.168.1.10] (unknown [82.233.253.129]) by smtp6-g21.free.fr (Postfix) with ESMTPS id 54ED4780304 for ; Wed, 13 Jul 2016 18:36:50 +0200 (CEST) In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: linux-acpi@vger.kernel.org Le 13 juillet 2016, Lucas Levrel a =E9crit : > Hi, > > I would like to adjust the temperature at which the fan starts, becau= se as it=20 > is now it runs continuously, at low speed but this continuous noise b= others=20 > me. I'd rather have it spin faster and intermittently. This is an HP = laptop. > > I've read much (mostly Q&A pages and list threads, regular documentat= ion=20 > seems to be scarce), and investigated the behaviour of files in=20 > /sys/devices/virtual/thermal . From what I understand there's no bug,= just=20 > the temperature thresholds are not to my taste. > > More specifically, there are 7 cooling_device's (4 of type Fan, 2 Pro= cessor,=20 > 1 LCD) and 5 thermal_zone's (the first 4 really are temperatures, the= last is=20 > the fan speed). thermal_zone0 controls the fan. The lowest trip_point= _?_temp=20 > (?=3D=3D4) is 45000, which is very low. Basically, after a few minute= s of idle=20 > operation temp reaches 50000 or 55000 (looks like there is 5 =B0C gra= nularity)=20 > and never gets lower: I've tried and manually set the fan to speed 2 = (echo 1=20 >> cooling_device2/cur_state), even then temp doesn't decrease below 50= 000. > > trip_point_?_temp are not writable. I've set thermal.act=3D60000 in t= he kernel=20 > command line, to no avail; is this supposed to be reflected in the=20 > trip_point_?_temp files? (Note: trip_point_[1-4]_type is "active".) T= his is=20 > kernel 3.2.71 . > > What can you advise me to do now? > > And by the way, for my education: > - how are the trip_point values determined? > - how is hysteresis implemented? I mean, you don't want your fan spee= d to=20 > change every other second, so the "speed up" threshold has to be high= er than=20 > the "speed down" one. In fact, I've found no explanation of how the=20 > trip_point values are used. > > Thanks. Hi again, After investigating some more, I found how hysteresis works: the=20 trip_point_?_temp changes when it is crossed. In my case,=20 trip_point_4_temp is 50000 at first (by default), and goes down to 4500= 0=20 when the fan starts. This is also why I saw no effect of thermal.act=3D60000 last time I tes= ted:=20 during boot the temperature reaches this threshold, and trip_point_4_te= mp=20 is set to 45000. I remain with the following questions: - how are the trip_point values determined? - is there a way to set them to taste? More specifically, I would like = to=20 rise the "fan stop" trigger temp; thermal.act=3D visibly didn't change=20 this... Thanks again. --=20 Lucas Levrel -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html