From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267367AbUHJAqv (ORCPT ); Mon, 9 Aug 2004 20:46:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267370AbUHJAqv (ORCPT ); Mon, 9 Aug 2004 20:46:51 -0400 Received: from gate.crashing.org ([63.228.1.57]:38356 "EHLO gate.crashing.org") by vger.kernel.org with ESMTP id S267367AbUHJAqt (ORCPT ); Mon, 9 Aug 2004 20:46:49 -0400 Subject: Re: [RFC] Fix Device Power Management States From: Benjamin Herrenschmidt To: Patrick Mochel Cc: Pavel Machek , Linux Kernel list , David Brownell In-Reply-To: References: <20040809113829.GB9793@elf.ucw.cz> Content-Type: text/plain Message-Id: <1092098630.14100.73.camel@gaston> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Tue, 10 Aug 2004 10:43:50 +1000 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > > Aha, so you are saying these do not need to be done in hardware order? > > AFAICT, no. As stated in my previous mail, I don't agree here... there are dependencies that cannot be dealt otherwise. USB was an example (ieee1394 is another), IDE is one, SCSI, i2c, whatever ... Of course, if we consider those "bus" drivers not to have class and thus not to be stopped and only the "leaf" devices to get stopped, that may work... I'm not sure we are not missing something there though... > > I believe different state is needed for "quiesce for atomic copy" and > > for "we are really going down to S4 now". > > There is nothing fundamentally different at the functional level - you > don't want any devices fulfilling any request. Besides, by the time the > system is actually ready to be placed in S4, the devices have long-since > been stopped, and the class devices do not need another notification > beyond "stop" > > Thanks, > > > Pat -- Benjamin Herrenschmidt