From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161363AbWKUXH5 (ORCPT ); Tue, 21 Nov 2006 18:07:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161413AbWKUXH5 (ORCPT ); Tue, 21 Nov 2006 18:07:57 -0500 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:23174 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S1161363AbWKUXH4 (ORCPT ); Tue, 21 Nov 2006 18:07:56 -0500 Date: Wed, 22 Nov 2006 00:07:44 +0100 From: Pavel Machek To: Tejun Heo Cc: kernel list , axboe@suse.de Subject: Re: SATA powersave patches Message-ID: <20061121230744.GD1995@elf.ucw.cz> References: <20060908123537.GB17640@elf.ucw.cz> <4501655F.5000103@gmail.com> <20060910224815.GC1691@elf.ucw.cz> <4505394F.6060806@gmail.com> <20060918100548.GJ3746@elf.ucw.cz> <450E771E.1070207@gmail.com> <20061106135751.GA13517@elf.ucw.cz> <454F747A.9050209@gmail.com> <20061112183927.GB5081@ucw.cz> <456280FE.70607@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <456280FE.70607@gmail.com> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > >>If I understood correctly, the high power consumption of > >>ahci controller can be solved by dynamically turning off > >>command processing while the controller is idle, which > >>fits nicely into link powersaving, right? So, I think > >>full-fledged leveled dynamic PM would be an overkill for > >>this particular problem, but then again, maybe the > > > >It is single bit, and it should not even need a timeout, AFAICT, so > >perhaps we should just fix it (no need for dynamic PM layers). It > >probably does not even need to be configurable... > > I think this has been discussed in linux-ide recently but just to add my > 2 cents. ALPE and ASP can cause quite some problems. Many devices > don't implement link powermanagement mode properly and some locks up Ok, so it needs to be optional :-). I played with the code a little bit, but did not find combination that both worked and saved power :-(. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html