Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754997AbXE3PiR (ORCPT ); Wed, 30 May 2007 11:38:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752172AbXE3PiF (ORCPT ); Wed, 30 May 2007 11:38:05 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:2996 "EHLO spitz.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751681AbXE3PiD (ORCPT ); Wed, 30 May 2007 11:38:03 -0400 Date: Wed, 30 May 2007 15:37:40 +0000 From: Pavel Machek To: "Rafael J. Wysocki" Cc: Alan Stern , pm list , LKML , Matthew Garrett , Nigel Cunningham , Oliver Neukum Subject: Re: [RFC][PATCH -mm 1/3] PM: Hibernation and suspend notifiers Message-ID: <20070530153740.GA4772@ucw.cz> References: <200705300024.32455.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200705300024.32455.rjw@sisk.pl> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2246 Lines: 49 Hi! > +Suspend notifiers > + (C) 2007 Rafael J. Wysocki , GPL > + > +There are some operations that device drivers may want to carry out in their > +.suspend() routines, but shouldn't, because they can cause the hibernation or > +suspend to fail. For example, a driver may want to allocate a substantial amount > +of memory (like 50 MB) in .suspend(), but that shouldn't be done after the > +swsusp's memory shrinker has run. > + > +Also, there may be some operations, that subsystems want to carry out before a > +hibernation/suspend or after a restore/resume, requiring the system to be fully > +functional, so the drivers' .suspend() and .resume() routines are not suitable > +for this purpose. For example, device drivers may want to upload firmware to > +their devices after a restore from a hibernation image, but they cannot do it by > +calling request_firmware() from their .resume() routines (user land processes > +are frozen at this point). The solution may be to load the firmware into > +memory before processes are frozen and upload it from there in the .resume() > +routine. Of course, a hibernation notifier may be used for this purpose. > + > +The subsystems that have such needs can register suspend notifiers that will be > +called upon the following events by the suspend core: > + > +PM_PRE_FREEZE The system is going to hibernate or suspend, tasks will > + be frozen immediately Hmm, looks like bad idea if we are going to remove freezer from suspend...? > +PM_POST_THAW Tasks have just been thawed after a resume or restore > + from a hibernation image > + > +PM_HIBERNATION_PREPARE The system is preparing for hibernation. Tasks have > + been frozen, memory is going to be freed and devices > + are going to be suspended. Is not PRE_FREEZE enough? We can allocate memory for drivers there, too... Pavel -- (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/