From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754580Ab1KCBcW (ORCPT ); Wed, 2 Nov 2011 21:32:22 -0400 Received: from out5.smtp.messagingengine.com ([66.111.4.29]:41590 "EHLO out5.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754496Ab1KCBcQ (ORCPT ); Wed, 2 Nov 2011 21:32:16 -0400 X-Sasl-enc: 76dh7LGj7qcaSTPeXqT0YYQL4B2J/YW6/RcNzhL6uh/n 1320283935 Date: Wed, 2 Nov 2011 18:31:27 -0700 From: Greg KH To: "Rafael J. Wysocki" Cc: Linus Walleij , Linux PM mailing list , Tejun Heo , Alan Stern , LKML , Magnus Damm , Kevin Hilman , linux-scsi@vger.kernel.org, Jesse Barnes , stable@kernel.org, Ulf Hansson Subject: Re: [PATCH 4/6 v2] PM: Limit race conditions between runtime PM and system sleep (v2) Message-ID: <20111103013127.GA3481@kroah.com> References: <201106260054.20578.rjw@sisk.pl> <20111102211708.GA19025@kroah.com> <201111030128.52823.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201111030128.52823.rjw@sisk.pl> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 03, 2011 at 01:28:52AM +0100, Rafael J. Wysocki wrote: > On Wednesday, November 02, 2011, Greg KH wrote: > > On Wed, Nov 02, 2011 at 10:00:39PM +0100, Linus Walleij wrote: > > > On Wed, Nov 2, 2011 at 9:11 PM, Greg KH wrote: > > > > On Wed, Nov 02, 2011 at 09:06:02PM +0100, Linus Walleij wrote: > > > >> On Wed, Nov 2, 2011 at 8:14 PM, Greg KH wrote: > > > >> > So, what specific git commits do you want to see in the 3.0-stable > > > >> > tree, and in what order should they be applied in? > > > >> > > > >> So to my untrained eye it looks like it should be applied like this (top to > > > >> bottom) using the reverse commit order from the mainline kernel: > > > >> > > > >> e529192 PM: Introduce generic "noirq" callback routines for subsystems (v2) > > > >> 455716e PM / Runtime: Update documentation of interactions with system sleep > > > >> 1e2ef05 PM: Limit race conditions between runtime PM and system sleep (v2) > > > >> f3393b6 PM / Runtime: Add new helper function: pm_runtime_status_suspended() > > > >> > > > >> So (2) documents the problem, (3) fixes it, whereas (1) and (4) makes > > > >> it possible > > > >> to write proper _noirq() code that does not race, IIRC. > > > > > > > > But, after this, it's just adding new infrastructure that drivers will > > > > then be able to use. As I'm not adding new drivers to 3.0, there will > > > > not be any users of this code, so why add it in the first place? It > > > > doesn't look like this follows the rules of the stable kernel tree at > > > > all, does it? > > > > > > We'll have to get some feedback from Rafael, but the way I percieved > > > it, the patch (2) fixes a very real race, then fixing that makes it > > > necessary for drivers using runtime_pm to do things differently to > > > be on the safe side. But none were really fixed when first merging > > > it. > > > > > > So on second thought you probably only want patch (2) > > > "PM: Limit race conditions between runtime PM and system sleep (v2)" > > > for stable. > > > > Ok, Rafael, any objection to me applying just this one? > > Well, I'd prefer not to unless there are reports confirming user problems > being fixed specifically by this patch. It changes the PM core's behavior > quite significantly and I'm a little afraid of possible regressions that may > result from it. Ok, good reason to not apply it, consider it dropped :) greg k-h