From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932948AbbKFAJ7 (ORCPT ); Thu, 5 Nov 2015 19:09:59 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:49721 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756455AbbKFAJ6 (ORCPT ); Thu, 5 Nov 2015 19:09:58 -0500 Date: Thu, 5 Nov 2015 16:09:57 -0800 From: Greg Kroah-Hartman To: "Rafael J. Wysocki" Cc: Grygorii Strashko , stern@rowland.harvard.edu, linux-pm@vger.kernel.org, Len Brown , Pavel Machek , linux-kernel@vger.kernel.org, Thierry Reding Subject: Re: [PATCH v2] PM / sleep: prohibit devices probing during suspend/hibernation Message-ID: <20151106000957.GB10347@kroah.com> References: <1445288064-25299-1-git-send-email-grygorii.strashko@ti.com> <5148641.xH2horsriG@vostro.rjw.lan> <19065758.fKD2xM4Ypl@vostro.rjw.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <19065758.fKD2xM4Ypl@vostro.rjw.lan> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 05, 2015 at 11:38:23PM +0100, Rafael J. Wysocki wrote: > On Monday, November 02, 2015 02:25:00 AM Rafael J. Wysocki wrote: > > On Monday, October 19, 2015 11:54:24 PM Grygorii Strashko wrote: > > > It is unsafe [1] if probing of devices will happen during suspend or > > > hibernation and system behavior will be unpredictable in this case > > > (for example: after successful probe the device potentially has a different > > > set of PM callbacks than before [2]). > > > So, let's prohibit device's probing in dpm_prepare() and defer their > > > probes instead. The normal behavior will be restored in dpm_complete(). > > > > > > This patch introduces new DD core APIs: > > > device_defer_all_probes_enable() > > > It will disable probing of devices and defer their probes. > > > device_defer_all_probes_disable() > > > It will restore normal behavior and trigger re-probing of deferred > > > devices. > > > > > > [1] https://lkml.org/lkml/2015/9/11/554 > > > [2] https://lkml.org/lkml/2015/9/15/1039 > > > Cc: Alan Stern > > > Cc: Rafael J. Wysocki > > > Cc: Thierry Reding > > > Signed-off-by: Grygorii Strashko > > > > Greg, any objections against this one? > > Greg, if this isn't problematic, I'd still like to take it for v4.4. What? The merge window for new stuff closed a few weeks ago, how can you add this for 4.4 when it needs to be in linux-next for a while first? I don't have any real objection to it, but I don't see how defering probing until "later" really solves anything, no one should be "changing pm callbacks" after some other probe succeeds, that sounds like someone just wants to have a broken system. thanks, greg k-h