linux-kernel - Re: [PATCH] PM: Prevent waiting forever on asynchronous suspend after abort

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Message-ID: <20120620151355.GC13770@kroah.com>
Date:	Wed, 20 Jun 2012 08:13:55 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	Alan Stern <stern@...land.harvard.edu>
Cc:	Mandeep Singh Baines <mandeep.baines@...il.com>,
	linux-kernel@...r.kernel.org, "Rafael J. Wysocki" <rjw@...k.pl>,
	Mandeep Singh Baines <msb@...omium.org>,
	linux-pm@...r.kernel.org, stable@...nel.org,
	Pavel Machek <pavel@....cz>, Len Brown <len.brown@...el.com>,
	Kevin Hilman <khilman@...com>,
	Colin Cross <ccross@...roid.com>,
	Sameer Nanda <snanda@...omium.org>,
	Olof Johansson <olofj@...omium.org>
Subject: Re: [PATCH] PM: Prevent waiting forever on asynchronous suspend
 after abort

On Wed, Jun 20, 2012 at 10:58:25AM -0400, Alan Stern wrote:
> On Tue, 19 Jun 2012, Mandeep Singh Baines wrote:
> 
> > __device_suspend() must always send a completion. Otherwise, parent
> > devices will wait forever.
> > 
> > Commit 1e2ef05b, "PM: Limit race conditions between runtime PM and
> > system sleep (v2)", introduced a regression by short-circuiting the
> > complete_all() for certain error cases.
> > 
> > This patch fixes the bug by always signalling a completion.
> > 
> > Addresses http://crosbug.com/31972
> > 
> > Tested by injecting an abort via the following patch:
> > 
> > diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c
> > index a004db3..e5a6fce 100644
> > --- a/drivers/usb/core/hcd-pci.c
> > +++ b/drivers/usb/core/hcd-pci.c
> > @@ -21,6 +21,7 @@
> >  #include <linux/pci.h>
> >  #include <linux/usb.h>
> >  #include <linux/usb/hcd.h>
> > +#include <linux/string.h>
> > 
> >  #include <asm/io.h>
> >  #include <asm/irq.h>
> > @@ -477,6 +478,8 @@ static int resume_common(struct device *dev, int event)
> > 
> >  static int hcd_pci_suspend(struct device *dev)
> >  {
> > +       if (!strcmp("0000:00:1d.3", dev_name(dev)))
> > +               return -EBUSY;
> >         return suspend_common(dev, device_may_wakeup(dev));
> >  }
> 
> When you include one patch in front of another like this, doesn't it 
> confuse the automatic tools?  You might end up getting both changes 
> include in the final commit.  :-)

Yeah, that's going to mess with quilt big time, I don't know what git is
going to do with it, it should be interesting to see...

greg k-h
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