Subject: Re: 2.6.12-rc1-mm1: resume regression [update] (was:
	Re:2.6.12-rc1-mm1: Kernel BUG at pci:389)
From: Li Shaohua <shaohua.li@intel.com>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
       Andrew Morton <akpm@osdl.org>, Greg KH <greg@kroah.com>,
       lkml <linux-kernel@vger.kernel.org>
In-Reply-To: <200503241442.14604.rjw@sisk.pl>
References: <1111626180.17317.921.camel@d845pe>
	 <1111627673.11775.6.camel@sli10-desk.sh.intel.com>
	 <200503241442.14604.rjw@sisk.pl>
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Date: Fri, 25 Mar 2005 08:49:59 +0800
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On Thu, 2005-03-24 at 21:42, Rafael J. Wysocki wrote:
> Hi,
> 
> On Thursday, 24 of March 2005 02:27, Li Shaohua wrote:
> > On Thu, 2005-03-24 at 09:03, Len Brown wrote:
> > > On Wed, 2005-03-23 at 18:49, Rafael J. Wysocki wrote:
> > > > Hi,
> > > > 
> > > > On Wednesday, 23 of March 2005 23:39, Pavel Machek wrote:
> > > > > Hi!
> > > > >
> > > > > > > > > Will this do it for the moment?
> > > > > > > >
> > > > > > > > Its certainly better.
> > > > > > >
> > > > > > > With the Len's patch applied I have to unload the modules:
> > > > > > >
> > > > > > > ohci_hcd
> > > > > > > ehci_hcd
> > > > > > > yenta_socket
> > > > > > >
> > > > > > > before suspend as each of them hangs the box solid during
> > > either
> > > > > > > suspend or resume.  Moreover, when I tried to load the
> > > ehci_hcd
> > > > > > > module back after resume, it hanged the box solid too.
> > > 
> > > Is this failure with suspend to RAM or to disk?
> > > 
> > > How about if you try this patch?
> > > 
> > > http://linux-acpi.bkbits.net:8080/to-akpm/cset@423b4875tyauh4CrSSoQfXOEPDkmUw
> > > 
> > > patch -Rp1 from 2.6.12-rc1-mm1 and see if it stops being broken
> > > or patch -Np1 to 2.6.12-rc and see if it starts being broken.
> > > 
> > > This one removes an earlier attempt at resuming PCI links -- now
> > > putting the onus on the drivers to be properly written
> > > to release and acquire their interrupt for a successful
> > > suspend/resume.
> > > 
> > > 
> > > In theory, this is taken care of something like this:
> > > driver.resume
> > >         pci_enable_device
> > >                 pci_enable_device_bars
> > >                         pcibios_enable_device
> > >                                 pcibios_enable_irq
> > >                                         acpi_pci_irq_enable
> > > 
> > > but if the patch above makes a difference, then theory != practice:-)
> 
> It looks like that. ;-)
> 
> > > I'd believe that ohci_hcd and ehci_hcd are fragile since glancing
> > > at their lengthy .resume routines it isn't immediately obvious
> > > that they do this.  But yenta_dev_resume has a pci_enable_device(),
> > > so that failure may be less straightforward.
> > > 
> > > cheers,
> > > -Len
> > > 
> > > ps. if point me to a full dmesg -s64000 from 2.6.12-rc1 acpi-enabled
> > > boot, that would help -- for it will show if we're even using pci
> > > interrupt links (and programming them) for these devices on this box.
> > Yes, we changed the behavior of device suspend/resume. Every PCI device
> > should call 'pci_disable_device' at suspend and call 'pci_enable_device'
> > at resume. It fixes a bug and more important thing is it's safer (Eg. it
> > disable interrupts, bus master and etc).
> > I actually added such calls in uhci, ehci and yenta. It's ok for S3 (and
> > definitely required for S3). Unclear if it's ok for S4, so please try
> > revert the patch.
> 
> 2.6.11-rc1-mm1 with the patch reverted works fine. :-)
So just remove the pci_enable/disable_device call in the driver makes
the system work? Strange, I tried them on two laptops (one HP nx5000,
and one Toshiba M2N), both works (no hang, and USB mouse works after
S3/S4. I didn't try yenta, since I have no pc card) for S3/S4. Is it
possible it's another bug or just because of different BIOS?

Thanks,
Shaohua

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