Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751569Ab2KPKGj (ORCPT ); Fri, 16 Nov 2012 05:06:39 -0500 Received: from ogre.sisk.pl ([193.178.161.156]:48300 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751029Ab2KPKGh (ORCPT ); Fri, 16 Nov 2012 05:06:37 -0500 From: "Rafael J. Wysocki" To: Huang Ying Cc: Alan Stern , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Subject: Re: [BUGFIX] PM: Fix active child counting when disabled and forbidden Date: Fri, 16 Nov 2012 11:10:59 +0100 Message-ID: <4327787.yACWT6Q3EK@vostro.rjw.lan> User-Agent: KMail/4.8.5 (Linux/3.7.0-rc5; KDE/4.8.5; x86_64; ; ) In-Reply-To: <1353029225.7176.314.camel@yhuang-dev> References: <1965322.pSDJypqR3K@vostro.rjw.lan> <1353029225.7176.314.camel@yhuang-dev> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1902 Lines: 47 On Friday, November 16, 2012 09:27:05 AM Huang Ying wrote: > On Fri, 2012-11-16 at 02:29 +0100, Rafael J. Wysocki wrote: > > On Friday, November 16, 2012 08:54:56 AM Huang Ying wrote: > > > On Fri, 2012-11-16 at 01:55 +0100, Rafael J. Wysocki wrote: > > > > On Friday, November 16, 2012 01:44:00 AM Rafael J. Wysocki wrote: > > > > > On Friday, November 16, 2012 08:36:14 AM Huang Ying wrote: > > > > > > On Thu, 2012-11-15 at 10:51 +0100, Rafael J. Wysocki wrote: > > > > > > > > [...] > > > > > > > > > > > > > > > > For this situation, if user "echo auto > .../power/control" for the > > > > > > device, the runtime PM callbacks of device will be called. I think that > > > > > > is not intended. So I think it is better to use some kind of flag or > > > > > > state for that. > > > > > > > > > > I'm not sure what situation exactly you have in mind. Care to give an > > > > > exact scenario? > > > > > > > > Ah, I see. When we've just called drv->remove(), there is a window in > > > > which user space may cause the driver's runtime PM callbacks to be > > > > executed by changing its attribute to "auto". > > > > > > > > So perhaps we should check pci_dev->driver rather than pci_dev->dev.driver > > > > in the runtime PM callbacks? With a few more changes that should allow us > > > > to close that race. > > > > > > Yes. And I think, with pci_dev->driver (after some changes suggested by > > > Alan), we need not to use pm_runtime_get/put_skip_callbacks(). > > > > Good. Can you please prepare a patch, then? :-) > > Sure. Cool, thanks! Rafael -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- 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/