Date: Thu, 14 Feb 2008 22:59:52 -0800
From: Greg KH <gregkh@suse.de>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Frans Pop <elendil@planet.nl>, linux-kernel@vger.kernel.org,
       linux-acpi@vger.kernel.org
Subject: Re: [2.6.25-rc1] System no longer powers off after shutdown
Message-ID: <20080215065952.GB8916@suse.de>
References: <200802111623.38478.elendil@planet.nl> <200802131239.14305.elendil@planet.nl> <20080213165837.GA10129@suse.de> <200802131955.53821.rjw@sisk.pl>
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On Wed, Feb 13, 2008 at 07:55:53PM +0100, Rafael J. Wysocki wrote:
> On Wednesday, 13 of February 2008, Greg KH wrote:
> > On Wed, Feb 13, 2008 at 12:39:13PM +0100, Frans Pop wrote:
> > > On Tuesday 12 February 2008, Greg KH wrote:
> > > > On Tue, Feb 12, 2008 at 09:39:14PM +0100, Frans Pop wrote:
> > > > > On Monday 11 February 2008, Frans Pop wrote:
> > > > > > In general 2.6.25 if looking quite good on my desktop, but there's
> > > > > > one important issue: the system no longer powers off after shutdown.
> > > > > > This works fine with 2.6.24.
> > > > >
> > > > > Don't ask me why, but bisection shows this commit to be the cause of
> > > > > the failure to power off:
> > > > > commit c10997f6575f476ff38442fa18fd4a0d80345f9d
> > > > > Author: Greg Kroah-Hartman <gregkh@suse.de>
> > > > > Date:   Thu Dec 20 08:13:05 2007 -0800
> > > > >
> > > > >     Kobject: convert drivers/* from kobject_unregister() to
> > > > > kobject_put()
> > > > >
> > > > > Because it seemed somewhat unlikely, I have double checked this by
> > > > > doing an extra compilation for this commit and its predecessor.
> > > >
> > > > What is the symptom of not powering off?
> > > 
> > > I already noticed yesterday that there's one hunk in that commit that's not
> > > a straight replacement:
> > > diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> > > index 9e102af..5efd555 100644
> > > --- a/drivers/cpufreq/cpufreq.c
> > > +++ b/drivers/cpufreq/cpufreq.c
> > > @@ -1030,8 +1030,6 @@ static int __cpufreq_remove_dev (struct sys_device * sys_dev)
> > > 
> > >         unlock_policy_rwsem_write(cpu);
> > > 
> > > -       kobject_unregister(&data->kobj);
> > > -
> > >         kobject_put(&data->kobj);
> > > 
> > >         /* we need to make sure that the underlying kobj is actually
> > > 
> > > 
> > > So, just on the off chance, I applied the patch below and bingo, the system
> > > powers off again. I doubt this will be the correct solution, but just in
> > > case it is, here's my signed off. A comment why the double put is needed
> > > would probably be good though.
> > 
> > There is a bug in the cpufreq kref logic that makes this "double put"
> > necessary.  A real fix has already been posted to solve this issue, and
> > I think it should be on it's way to Linus for -rc2 already.
> > 
> > Please let me know if -rc2 comes out without this needed fix.
> 
> Can you point me to the fix, please?

I swear someone else sent this in, but my archives don't show it at all.

I think the patch below should solve this, but I need someone to test
it.

thanks,

greg k-h

---
 drivers/cpufreq/cpufreq.c |    8 --------
 1 file changed, 8 deletions(-)

--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -1006,14 +1006,6 @@ static int __cpufreq_remove_dev (struct 
 	}
 #endif
 
-
-	if (!kobject_get(&data->kobj)) {
-		spin_unlock_irqrestore(&cpufreq_driver_lock, flags);
-		cpufreq_debug_enable_ratelimit();
-		unlock_policy_rwsem_write(cpu);
-		return -EFAULT;
-	}
-
 #ifdef CONFIG_SMP
 
 #ifdef CONFIG_HOTPLUG_CPU
--
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