From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kristen Carlson Accardi Subject: Re: [PATCH] ata: ahci: power off unused ports Date: Mon, 2 Jun 2008 09:57:10 -0700 Message-ID: <20080602095710.1b0de376@appleyard> 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> Reply-To: kristen.c.accardi@intel.com Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mga02.intel.com ([134.134.136.20]:47786 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752962AbYFBRGg (ORCPT ); Mon, 2 Jun 2008 13:06:36 -0400 In-Reply-To: <4843EF88.2040606@rtr.ca> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mark Lord Cc: Jeff Garzik , Alan Cox , Pavel Machek , Theodore Tso , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org On Mon, 02 Jun 2008 09:03:04 -0400 Mark Lord wrote: > Jeff Garzik wrote: > > Alan Cox wrote: > >>> If you are talking about SATA -- incorrect. > >>> > >>> The patch deals with policy, and the user MUST have the ability to > >>> control this stuff. Otherwise you create a situation where the user > >>> might be denied hotplug use in valid cases, or similar negative > >>> situations. > >> > >> The policy isn't however complicated. Tejun added the stuff for forcing > >> cable type and mode on setup and has therefore written all the per device > >> setup code we might need. Alternatively a single > >> > >> foo=1/0 > >> > >> option has been fine for acpi and will do fine for this. Total additional > >> cost - 1 line. > > > > The key requirement is per-port control. Ideally via hdparm or another > > userspace tool, but kernel command line (module options) or sysfs would > > be just fine too. And agreed, the minimal you need is simply 1/0 for > > the port's policy. > .. > > Btw.. hdparm-8.7 (unreleased) can grok /sys now, so that interface is > as good as any from a userspace viewpoint now. > > For the power-off of unused ports, the current patch still sounds > extremely vendor-specific (Intel). Wrong - this patch is implemented according to the AHCI spec and has absolutely nothing vendor specific in it. > > Does it actually work (demonstrate, please) on any other hardware ? If someone would like to test it on another AHCI compliant chipset that would be great. I have none.