Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754801AbZLTAJa (ORCPT ); Sat, 19 Dec 2009 19:09:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754607AbZLTAJ3 (ORCPT ); Sat, 19 Dec 2009 19:09:29 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:36788 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754487AbZLTAJ2 (ORCPT ); Sat, 19 Dec 2009 19:09:28 -0500 Date: Sat, 19 Dec 2009 16:09:07 -0800 (PST) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: "Rafael J. Wysocki" cc: Dmitry Torokhov , Alan Stern , Zhang Rui , LKML , ACPI Devel Maling List , pm list Subject: Re: Async suspend-resume patch w/ completions (was: Re: Async suspend-resume patch w/ rwsems) In-Reply-To: <200912200053.45988.rjw@sisk.pl> Message-ID: References: <200912200040.18944.rjw@sisk.pl> <200912200053.45988.rjw@sisk.pl> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1899 Lines: 45 On Sun, 20 Dec 2009, Rafael J. Wysocki wrote: > > > > Why would it be? > > The embedded controller may depend on it. Again, I say "why?" Anything can be true. That doesn't _make_ everything true. There's no real reason why PnP/ACPI suspend/resume should really care. We can try it. Not for 2.6.33, but by the 34 merge window maybe we'll have a patch-series that is ready to be tested, and that aggressively tries to do the devices that matter asynchronously. So instead of you trying to make up some idiotic cross-device worries, just see if those worries have any actual background in reality. So far I haven't actually heard anything but "in theory, anything is possible", which is such a truism that it's not even worth voicing. That said, I still get the feeling that we'd be even better off simply trying to avoid the whole keyboard reset entirely. Apparently we do it for a few HP laptops. It's entirely possible that we'd be better off simply not _doing_ the slow thing in the first place. For example, we may be _much_ better off doing that whole keyboard reset at resume time than at suspend time. That's what we do when we probe things on initialization - and the resume-time keyboard code is actually already asynchronous, it does that atkbd_reconnect asynchronously by queuing it as an event. So again, all these problems may not at all be fundamnetal problems: the keyboard driver does certain things, but there is no guarantee that it _needs_ to do those things. Turning the driver async may be totally the wrong thing to do, when we could potentially fix latency problems at the driver level instead. Linus -- 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/