Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753400AbXFDLBN (ORCPT ); Mon, 4 Jun 2007 07:01:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752896AbXFDLA7 (ORCPT ); Mon, 4 Jun 2007 07:00:59 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:59901 "EHLO amd.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752287AbXFDLA6 (ORCPT ); Mon, 4 Jun 2007 07:00:58 -0400 Date: Mon, 4 Jun 2007 13:00:52 +0200 From: Pavel Machek To: Alan Stern Cc: Matthew Garrett , "Rafael J. Wysocki" , pm list , LKML , Nigel Cunningham , Oliver Neukum Subject: Re: [RFC][PATCH -mm 3/3] PM: Disable _request_firmware before hibernation/suspend Message-ID: <20070604110052.GI4363@elf.ucw.cz> References: <20070528205727.GA5911@ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1783 Lines: 38 Hi! > > > The theoretical answer is that it behaves the way we want. The kernel > > > thread does selective resumes in response to device requests. If such > > > a request comes in while the system is asleep it will awaken the > > > system; so it's only logical that a request coming in while the system > > > is in the process of going to sleep should abort the suspend. > > > > I'd say that it shows ppc being broken. User wanted to suspend the > > system, and now unrelated task did lsusb... and system will not sleep. > > > > AFAICT it is DoS issue -- if one of your users keeps doing lsusb, root > > will not be able to suspend the system. > > This is a matter of one's philosophy. In suspend-to-RAM, should tasks > be frozen or should I/O queues be frozen? > > With the USB subsystem I have followed the approach taken by the PM > core, which is that tasks are frozen. But one can -- and Linus has on > at least one occasion -- make a good case that tasks should be left > running while only I/O is frozen. This would require the subsystem to > distinguish between a selective device suspend and a system-wide > suspend-to-RAM, so that selective resume could be enabled on demand in > one case but not the other. > > It's quite doable in principle -- it's just not the technique I used. I guess we need to do that. Random user should not be able to prevent machine from sleeping. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - 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/