From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ric Wheeler Subject: Re: [PATCH] ata: ahci: power off unused ports Date: Mon, 02 Jun 2008 14:30:20 -0400 Message-ID: <48443C3C.3010401@redhat.com> References: <20080508161008.59361de5@appleyard> <20080527030854.GC7515@mit.edu> <20080527143202.4bab5bf0@appleyard> <20080527225926.GE6843@mit.edu> <20080527163251.04054a74@appleyard> <20080531080015.GG5405@ucw.cz> <4842F5A8.9020708@garzik.org> <20080602080440.25fc663c@core> <4843A4A7.3020809@garzik.org> <4843EF88.2040606@rtr.ca> <48441AA6.8080704@garzik.org> <20080602100019.3d2d2522@appleyard> <484431AB.7010005@garzik.org> <20080602104753.3f24087d@appleyard> <484438BF.7070303@garzik.org> <20080602111644.54738d57@appleyard> Reply-To: rwheeler@redhat.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([66.187.233.31]:41323 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752061AbYFBSaE (ORCPT ); Mon, 2 Jun 2008 14:30:04 -0400 In-Reply-To: <20080602111644.54738d57@appleyard> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: kristen.c.accardi@intel.com Cc: Jeff Garzik , Mark Lord , Alan Cox , Pavel Machek , Theodore Tso , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Kristen Carlson Accardi wrote: > On Mon, 02 Jun 2008 14:15:27 -0400 > Jeff Garzik wrote: > > >> Kristen Carlson Accardi wrote: >> >>> Here you can see that it would be very easy for another driver >>> to just add code to set the NO_HOTPLUG flag and then this code >>> will work for them as well, since we power off the phy using >>> DET which is specified by SATA. >>> >>> here's that code: >>> >> Agreed. The main discussion in this sub-thread is more about user >> interface. The user interface in this case, a module option, is >> specific to AHCI. >> >> Surely you can see how it is a bit silly to force each driver writer to >> create the same user interface in each driver, to support a generic concept. >> >> Jeff >> >> >> > Not all drivers will need a user interface to turn off hotplug > I would think. At any rate - I would think it'd be better to let > driver writers decide how they want their drivers to behave wrt > hotplug and power instead of forcing a generic policy on everyone. > > This patch would provide users of AHCI controllers a way to save > power now, while you work on the grand scheme for polling/turning on off > hotplug via sysfs. It's an interim solution that impacts nobody but > ahci users and is can be easily integrated into whatever solution you > eventually work out. > I like the patch - it seems that it will help a lot of users out near term in a very positive way while we iterate on the broader solution, ric