Re: [PATCH] PCI: Add pci shutdown ability

From: Benjamin Herrenschmidt
Date: Mon Apr 25 2005 - 23:35:21 EST

> > So if I understand this correctly, you'd like to manually turn off devices
> > during a power off. I believe the ACPI spec recommends this for S4 (but also
> > to leave on wake devices), but not necessarily S5. Still it may be a good
> > idea. Comments?
> It is neccessary for some machines (interrupt controller) or machine
> will not power down...

Additionally, some machines won't properly park/flush the disk, it's
necessary to send the proper suspend commands to IDE hard disks prior to
shutting down or we risk data loss.

> > > Actually this patch should be in the queue somewhere... We had it in
> > > suse trees for a long time, and IMO it can solve problem easily.
> >
> > Yeah, that's what I had in mind when I mentioned PMSG_FREEZE. It seems
> > to replace "shutdown" in many ways, is this correct?
> Yes. (Actually I'm not sure if PMSG_FREEZE or PMSG_SUSPEND is right
> thing to do for suspend.)

I think FREEZE for kexec and SUSPEND for shutdown, though I suppose we
may want a separate one for the later eventually...


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