linux-kernel - RE: [linux-pm] [PATCH] PM: Fixes warning on suspend errors

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Date:	Tue, 27 Oct 2009 20:00:51 +0530
From:	"Dasgupta, Romit" <romit@...com>
To:	Alan Stern <stern@...land.harvard.edu>
CC:	"Hilman, Kevin" <khilman@...com>, "rjw@...k.pl" <rjw@...k.pl>,
	"linux-pm@...ts.linux-foundation.org" 
	<linux-pm@...ts.linux-foundation.org>,
	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [linux-pm] [PATCH] PM: Fixes warning on suspend errors

Ok. Then the following is the refined and probably more appropriate one.



This fixes the point where we need to complete the power transition when 
device suspend fails.

Signed-off-by: Romit Dasgupta <romit@...com>
---

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index e0dc407..3d0b26a 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -444,6 +444,7 @@ static void dpm_resume(pm_message_t state)
 
 	INIT_LIST_HEAD(&list);
 	mutex_lock(&dpm_list_mtx);
+	transition_started = false;
 	while (!list_empty(&dpm_list)) {
 		struct device *dev = to_device(dpm_list.next);





> -----Original Message-----
> From: linux-omap-owner@...r.kernel.org [mailto:linux-omap-
> owner@...r.kernel.org] On Behalf Of Alan Stern
> Sent: Tuesday, October 27, 2009 7:08 PM
> To: Dasgupta, Romit
> Cc: Hilman, Kevin; rjw@...k.pl; linux-pm@...ts.linux-foundation.org; linux-
> omap@...r.kernel.org; linux-kernel@...r.kernel.org
> Subject: Re: [linux-pm] [PATCH] PM: Fixes warning on suspend errors
> 
> On Tue, 27 Oct 2009, Dasgupta, Romit wrote:
> 
> > Hi,
> >      I get the following errors when I choose devices in /sys/power/pm_test. It
> also shows that if 'dpm_suspend_start' fails somewhere down the line then
> the kernel does not reset the 'transition_started' variable and we can get
> warning similar to below. IMHO 'dpm_resume_noirq' is not the right place for
> setting this variable. Please see the patch below which fixes the issue.
> 
> > Fixes the location where we decide that our power transition is complete.
> > Signed-off-by: Romit Dasgupta <romit@...com>
> > ---
> > diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> > index e0dc407..6b9e991 100644
> > --- a/drivers/base/power/main.c
> > +++ b/drivers/base/power/main.c
> > @@ -365,7 +365,6 @@ void dpm_resume_noirq(pm_message_t state)
> >  	struct device *dev;
> >
> >  	mutex_lock(&dpm_list_mtx);
> > -	transition_started = false;
> >  	list_for_each_entry(dev, &dpm_list, power.entry)
> >  		if (dev->power.status > DPM_OFF) {
> >  			int error;
> > @@ -529,6 +528,7 @@ static void dpm_complete(pm_message_t state)
> >  		put_device(dev);
> >  	}
> >  	list_splice(&list, &dpm_list);
> > +	transition_started = false;
> >  	mutex_unlock(&dpm_list_mtx);
> >  }
> 
> The second hunk is okay, but the first hunk isn't.  We want to set
> transition_started to false as soon as devices start resuming, because
> once a resume has begun it's okay to add new devices.
> 
> Alan Stern
> 
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