Re: [PATCH] PCI: Add pci shutdown ability

[Greg KH]

On Mon, Apr 25, 2005 at 03:23:09PM -0400, Jeff Garzik wrote:
> Greg KH wrote:
> >Well it seems that people are starting to want to hook the reboot
> >notifier, or the device shutdown facility in order to properly shutdown
> >pci drivers to make kexec work nicer.
> >
> >So here's a patch for the PCI core that allows pci drivers to now just
> >add a "shutdown" notifier function that will be called when the system
> >is being shutdown.  It happens just after the reboot notifier happens,
> >and it should happen in the proper device tree order, so everyone should
> >be happy.
> >
> >Any objections to this patch?
> 
> Traditionally the proper place -has- been
> * the reboot notifier
> * the ->remove hook (hot unplug, and module remove)

The latter doesn't get called on power-down, which is what the recent
patches for the kexec "fixes" seem to want.

> which covers all the cases.

But do we really want every pci driver adding a reboot notifier?  It's
simple, yes, but a lot of extra code everywhere, that I'm pretty sure
the shutdown() hook was ment to handle.

> Add a ->shutdown hook is more of a hack.  If you want to introduce this 
> facility in a systematic way, introduce a 'kexec reboot' option which 
> walks the device tree and shuts down hardware.

Why would "kexec reboot" be any different from the "normal" system
shutdown?

> ->shutdown is just a piecemeal, uncoordinated effort (uncoordinated in 
> the sense that driver shutdowns occur in an undefined order).

->shutdown looks like it walks the device tree and shuts down the
hardware in the proper order, why do you think it is an undefined order?

thanks,

greg k-h
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