Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760804AbYFBNDT (ORCPT ); Mon, 2 Jun 2008 09:03:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756115AbYFBNDK (ORCPT ); Mon, 2 Jun 2008 09:03:10 -0400 Received: from rtr.ca ([76.10.145.34]:3835 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754391AbYFBNDJ (ORCPT ); Mon, 2 Jun 2008 09:03:09 -0400 Message-ID: <4843EF88.2040606@rtr.ca> Date: Mon, 02 Jun 2008 09:03:04 -0400 From: Mark Lord Organization: Real-Time Remedies Inc. User-Agent: Thunderbird 2.0.0.14 (X11/20080421) MIME-Version: 1.0 To: Jeff Garzik Cc: Alan Cox , Pavel Machek , Kristen Carlson Accardi , Theodore Tso , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ata: ahci: power off unused ports 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> In-Reply-To: <4843A4A7.3020809@garzik.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1696 Lines: 44 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). Does it actually work (demonstrate, please) on any other hardware ? I would still like to see a far more generic solution, with periodic polling and the like, which would permit use on *any* machines (eg. data centers) without loss of hotplug capability on those ports. But that's probably just wishful thinking at this point. Cheers -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/