From mboxrd@z Thu Jan 1 00:00:00 1970 From: Huang Ying Subject: Re: [BUGFIX] PM: Fix active child counting when disabled and forbidden Date: Fri, 16 Nov 2012 09:27:05 +0800 Message-ID: <1353029225.7176.314.camel@yhuang-dev> References: <5403446.Qq6ASJZlmy@vostro.rjw.lan> <1353027296.7176.312.camel@yhuang-dev> <1965322.pSDJypqR3K@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mga02.intel.com ([134.134.136.20]:61268 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751166Ab2KPB1I (ORCPT ); Thu, 15 Nov 2012 20:27:08 -0500 In-Reply-To: <1965322.pSDJypqR3K@vostro.rjw.lan> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Rafael J. Wysocki" Cc: Alan Stern , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org 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. Best Regards, Huang Ying