From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754846AbbAZLFW (ORCPT ); Mon, 26 Jan 2015 06:05:22 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:36390 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752075AbbAZLFS (ORCPT ); Mon, 26 Jan 2015 06:05:18 -0500 Date: Mon, 26 Jan 2015 12:05:16 +0100 From: Pavel Machek To: "Liu, Chuansheng" Cc: "Fu, Zhonghui" , "Rafael J. Wysocki" , "Brown, Len" , Greg Kroah-Hartman , "linux-pm@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: Change behaviour when tracing ... nasty trap (was Re: [PATCH] PM/Trace: get rid of synchronous resume limit during PM trace) Message-ID: <20150126110516.GA2028@amd> References: <54C5CB77.4000109@linux.intel.com> <20150126102352.GA1758@amd> <27240C0AC20F114CBF8149A2696CBE4A01F1AD6A@SHSMSX101.ccr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <27240C0AC20F114CBF8149A2696CBE4A01F1AD6A@SHSMSX101.ccr.corp.intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 2015-01-26 10:39:04, Liu, Chuansheng wrote: > Hello Pavel, > > > > There are some kind of dependency between devices in some > > > hardware platforms. So, asynchronous resuming devices may > > > hang system due to wrong resume order. As a result, should > > > not fore synchronously resuming devices during tracing > > > PM events. > > > > > > Signed-off-by: Zhonghui Fu > > > --- > > > drivers/base/power/main.c | 3 +-- > > > include/linux/resume-trace.h | 7 ------- > > > 2 files changed, 1 insertions(+), 9 deletions(-) > > > > > > diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c > > > index 9717d5f..5df148b 100644 > > > --- a/drivers/base/power/main.c > > > +++ b/drivers/base/power/main.c > > > @@ -517,8 +517,7 @@ static int device_resume_noirq(struct device *dev, > > pm_message_t state, bool asyn > > > > > > static bool is_async(struct device *dev) > > > { > > > - return dev->power.async_suspend && pm_async_enabled > > > - && !pm_trace_is_enabled(); > > > + return dev->power.async_suspend && pm_async_enabled; > > > } > > > > > > > Actually... whoever did the original patch was evil person. Changing > > behaviour when tracing is requested is evil, evil, evil. Git blame > > tells me > > > > Signed-off-by: Chuansheng Liu > > > > went to the dark side. > > Although I didn't get where is something wrong, but the is_async() is not created by my commit, > it is from commit (PM: Start asynchronous resume threads upfront), I just moved it ahead. > > And like other phases, I added it into resum/suspend_noirq()... I see, blame blamed wrong person. It looks like Rafael is evil: commit 97df8c12995c5bac73e3bfeea4c5be155c1f4401 Author: Rafael J. Wysocki Date: Sat Jan 23 22:25:31 2010 +0100 PM: Start asynchronous resume threads upfront Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html