Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753999Ab2HMWAn (ORCPT ); Mon, 13 Aug 2012 18:00:43 -0400 Received: from ogre.sisk.pl ([193.178.161.156]:36743 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753648Ab2HMWAl (ORCPT ); Mon, 13 Aug 2012 18:00:41 -0400 From: "Rafael J. Wysocki" To: Alan Stern Subject: Re: [PATCH][Alternative][RFC] PM / Runtime: Introduce driver runtime PM work routine Date: Tue, 14 Aug 2012 00:06:37 +0200 User-Agent: KMail/1.13.6 (Linux/3.5.0+; KDE/4.6.0; x86_64; ; ) Cc: Linux PM list , Ming Lei , LKML , "Greg Kroah-Hartman" References: In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201208140006.37977.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1548 Lines: 36 On Monday, August 13, 2012, Alan Stern wrote: > On Mon, 13 Aug 2012, Rafael J. Wysocki wrote: > > > > I guess the best we can say is that if you call pm_runtime_barrier() > > > after updating the dev_pm_ops method pointers then after the barrier > > > returns, the old method pointers will not be invoked and the old method > > > routines will not be running. So we need an equivalent guarantee with > > > regard to the pm_runtime_work pointer. (Yes, we could use a better > > > name for that pointer.) > > > > > > Which means the code in the patch isn't quite right, because it saves > > > the pm_runtime_work pointer before calling rpm_resume(). Maybe we > > > should avoid looking at the pointer until rpm_resume() returns. > > > > Yes, we can do that. > > > > Alternatively, we can set power.work_in_progress before calling > > rpm_resume(dev, 0) (i.e. regard the resume as a part of the work) to make > > the barrier wait for all of it to complete. > > Yep, that would work. In fact, I did it that way in the proposed code > posted earlier in this thread. (But that was just on general > principles, not because I had this particular race in mind.) OK I need to prepare a new patch now, but first I'll send a couple of (minor) fixes for the core runtime PM code. Thanks, Rafael -- 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/