From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yanmin Zhang Subject: Re: [PATCH] PM: avoid 'autosleep' in shutdown progress Date: Fri, 12 Jul 2013 14:14:11 +0800 Message-ID: <1373609651.4432.122.camel@ymzhang.sh.intel.com> References: <1373529825-20741-1-git-send-email-shuox.liu@intel.com> Reply-To: yanmin_zhang@linux.intel.com Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mga03.intel.com ([143.182.124.21]:28067 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752554Ab3GLGO3 (ORCPT ); Fri, 12 Jul 2013 02:14:29 -0400 In-Reply-To: <1373529825-20741-1-git-send-email-shuox.liu@intel.com> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: shuox.liu@intel.com Cc: linux-kernel@vger.kernel.org, len.brown@intel.com, pavel@ucw.cz, rjw@sisk.pl, linux-pm@vger.kernel.org On Thu, 2013-07-11 at 16:03 +0800, shuox.liu@intel.com wrote: > From: Liu ShuoX > > In shutdown progress, system is possible to do power transition > (such as suspend-to-ram) in parallel. It is unreasonable. So, > fixes it by adding a system_state checking and queue try_to_suspend > again when system status is not running. > > Signed-off-by: Liu ShuoX > --- > kernel/power/autosleep.c | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > Without this patch, we hit an hang issue on Android. Scenario: Kernel starts shutdown and calls all device driver's shutdown callback. When a driver's shutdown is called, the last wakelock is released and suspend-to-ram starts. However, as some driver's shut down callbacks already shut down devices and disable runtime pm, the suspend-to-ram calls driver's suspend callback without noticing that device is already off and causes crash. We know the drivers should be fixed, but can we also change generic codes a little to make it stronger? > diff --git a/kernel/power/autosleep.c b/kernel/power/autosleep.c > index c6422ff..9012ecf 100644 > --- a/kernel/power/autosleep.c > +++ b/kernel/power/autosleep.c > @@ -32,7 +32,8 @@ static void try_to_suspend(struct work_struct *work) > > mutex_lock(&autosleep_lock); > > - if (!pm_save_wakeup_count(initial_count)) { > + if (!pm_save_wakeup_count(initial_count) || > + system_state != SYSTEM_RUNNING) { > mutex_unlock(&autosleep_lock); > goto out; > }