From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759487Ab3BYKU4 (ORCPT ); Mon, 25 Feb 2013 05:20:56 -0500 Received: from mail.skyhub.de ([78.46.96.112]:51128 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758806Ab3BYKUy (ORCPT ); Mon, 25 Feb 2013 05:20:54 -0500 Date: Mon, 25 Feb 2013 11:20:49 +0100 From: Borislav Petkov To: Zhang Rui Cc: Peter Feuerer , LKML , Durgadoss R , Borislav Petkov , Andreas Mohr , Alexander Lam Subject: Re: [PATCH] acerhdf: Fix fan activation with new thermal governor Message-ID: <20130225102049.GA12067@pd.tnic> Mail-Followup-To: Borislav Petkov , Zhang Rui , Peter Feuerer , LKML , Durgadoss R , Borislav Petkov , Andreas Mohr , Alexander Lam References: <20130222111521.GA25473@pd.tnic> <1361647210-12983-1-git-send-email-bp@alien8.de> <20130224112851.GA19609@pd.tnic> <20130224120952.GB19609@pd.tnic> <1361761600.2303.12.camel@rzhang1-mobl4> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1361761600.2303.12.camel@rzhang1-mobl4> 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 Mon, Feb 25, 2013 at 11:06:40AM +0800, Zhang Rui wrote: > when the temperature goes up to 50C, will the fan be turned on or not? Right, let's first clarify this: so we want the fan to go on when it reaches and/or exceeds the 'fanon' temperature and to go off after it goes under the 'fanoff' temperature. It is supposed to remain on in the [fanoff,fanon] interval. Now, my observation from yesterday was that, if we don't do the flattening of the abovementioned interval in acerhdf_set_cur_state() but we simply turn on the fan if we receive state=1 and turn it off when state=0, the fan gets turned on only for short bursts when the governor decides it is time to throttle, i.e. the temperature in the zone is rising and turns it off when the temperature starts to fall again. And it would turn on the fan at lower temperatures than fanon. But this is annoying. The main reason why this acerhdf thing was added in the first place was to do a better fan control on those machines because the fans are noisy. Basically, enable the fan only when really needed - and leave it off when not because it is really annoying. When enabled, however, leave it on longer until a safe, 'fanoff' temperature is reached. Am I making more sense now? Peter? Thanks. -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --