Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261584AbVDZPOo (ORCPT ); Tue, 26 Apr 2005 11:14:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261579AbVDZPOe (ORCPT ); Tue, 26 Apr 2005 11:14:34 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:7296 "HELO iolanthe.rowland.org") by vger.kernel.org with SMTP id S261568AbVDZPON (ORCPT ); Tue, 26 Apr 2005 11:14:13 -0400 Date: Tue, 26 Apr 2005 11:14:10 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Benjamin Herrenschmidt cc: Dave Jones , Andrew Morton , , Greg KH , , Linux Kernel list , , Jeff Garzik , , Linux-USB Subject: Re: [PATCH] PCI: Add pci shutdown ability In-Reply-To: <1114487537.7182.26.camel@gaston> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 947 Lines: 21 On Tue, 26 Apr 2005, Benjamin Herrenschmidt wrote: > The problem is, as far as I understand what David told me a while ago, > some USB chips simply _cannot_ disable DMA without actually suspending > the bus, which itself is a complex process that takes some time and can > involve all sort of problems with devices / drivers that don't deal with > suspended busses properly. I suspect other kind of chips may be > similarily busted by design. That's correct. However, during shutdown we don't really need to take the time and we don't care about problems with drivers not handling suspended buses properly. (USB devices, at least, _can_ handle such things -- it's part of the spec.) Alan Stern - 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/