Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756470AbYHMQUj (ORCPT ); Wed, 13 Aug 2008 12:20:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751583AbYHMQUa (ORCPT ); Wed, 13 Aug 2008 12:20:30 -0400 Received: from ns1.suse.de ([195.135.220.2]:50233 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751116AbYHMQU3 convert rfc822-to-8bit (ORCPT ); Wed, 13 Aug 2008 12:20:29 -0400 From: Oliver Neukum Organization: Novell To: linux-pm@lists.linux-foundation.org Subject: Re: [linux-pm] Power management for SCSI Date: Wed, 13 Aug 2008 18:21:29 +0200 User-Agent: KMail/1.9.9 Cc: Alan Stern , James.Bottomley@hansenpartnership.com, Pavel Machek , "Linux-pm mailing list" , kernel list , teheo@novell.com References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200808131821.30564.oneukum@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1004 Lines: 23 Am Mittwoch 13 August 2008 17:44:46 schrieb Alan Stern: > > All children that are USB must be powered down. We know in fact that most > > drives don't care that the device is suspended. The problem was drive > > enclosures that cut power upon suspension losing cached data. > > You misunderstood my question. ?Are there SCSI transports other than > USB sharing the requirement that all child devices must be suspended > before the link can be powered down? I dispute that USB in general has this property. Some storage devices need their caches flushed. USB itself is perfectly happy with autosuspending the storage device (host) without telling the disks (devices) You could even argue that these storage devices violate the USB spec. Regards Oliver -- 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/