Re: [patch] properly stop devices before poweroff

Andrew Morton
2005-05-16T07:56:39Z

Adam Belay <ambx1@neo.rr.com> wrote:
>
> On Mon, May 02, 2005 at 04:09:08AM +0900, Kenji Kaneshige wrote:
> > Hi,
> >
> > Andrew Morton wrote:
> > >Pavel Machek <pavel@ucw.cz> wrote:
> > >
> > >>
> > >>Without this patch, Linux provokes emergency disk shutdowns and
> > >>similar nastiness. It was in SuSE kernels for some time, IIRC.
> > >>
> > >
> > >
> > >With this patch when running `halt -p' my ia64 Tiger (using
> > >tiger_defconfig) gets a stream of badnesses in iosapic_unregister_intr()
> > >and then hangs up.

A little reminder that this bug remains unfixed...

> > >Unfortunately it all seems to happen after the serial port has been
> > >disabled because nothing comes out. I set the console to a squitty font
> > >and took a piccy. See
> > >http://www.zip.com.au/~akpm/linux/patches/stuff/dsc02505.jpg
> > >
> > >I guess it's an ia64 problem. I'll leave the patch in -mm for now.
> > >
> >
> > I guess the stream of badness was occured as follows:
> >
> > pcibios_disable_device() for ia64 assumes that pci_enable_device()
> > and pci_disable_device() are balanced. But with 'properly stop
> > devices before power off' patch, pci_disable_device() becomes to be
> > called twice for e1000 device at halt time, through reboot_notifier_list
> > callback and through device_suspend(). As a result,
> > iosapic_unregister_intr()
> > was called for already unregistered gsi and then stream of badness
> > was displayed.
> >
> > I think the following patch will remove this stream of badness. I'm
> > sorry but I have not checked if the stream of badness is actually
> > removed because I'm on vacation and I can't look at my display
> > (I'm working via remote console). Could you try this patch?
> >
> > By the way, I don't think this stream of badness is related to hang up,
> > because the problem (hang up) was reproduced even on my test kernel that
> > doesn't call pcibios_disable_device().
> >
> > Thanks,
> > Kenji Kaneshige
> > ---
> >
> >
> > There might be some cases that pci_disable_device() is called even if
> > the device is already disabled. In this case, pcibios_disable_device()
> > should not call acpi_pci_irq_disable() for the device.
> >
> > Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
> >
>
> Although this would solve the problem, it may or may not be the right thing to
> do. The bug is not in pci_disable_device(), it's in the fact that we're
> calling pci_disable_device() twice. Whether pci_disable_device() should ignore
> this or create an error is an implementation decision. It might make sense to
> have it print a warning. Greg, what are your thoughts?
>
> What's important is that we don't want to suspend the device twice (in this
> case suspend and reboot_notifier).
>
> Thanks,
> Adam
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