Re: [linux-pm] [RFC] ACPI vs device ordering on resume

[Stephen Hemminger <shemminger@osdl.org>]

On Fri, 01 Dec 2006 20:45:51 +0300
Alexey Starikovskiy <alexey.y.starikovskiy@linux.intel.com> wrote:

> Linus Torvalds wrote:
> > On Fri, 1 Dec 2006, Pavel Machek wrote:
> >
> >   
> >>>> So it looks like we need this sequence:
> >>>>
> >>>> enable_nonboot_cpus() /* INIT */
> >>>> finish()	/* _WAK */
> >>>> device_resume()
> >>>>         
> >>> Can somebody remind me about this immediately after 2.6.19?
> >>>       
> >> Remind. But note that freezer is not yet SMP safe... Rafael is working
> >> on that.
> >>     
> >
> > Thanks.
> >
> > On the other hand, I really wonder (and suspect) whether the problem isn't 
> > really the freezer or even the kernel resume ordering, but simply an ACPI 
> > internal resume ordering thing.
> >
> > Doesn't ACPI have per-device "WAK" calls anyway? Shouldn't we just call 
> > those _individually_ as we walk the device tree (perhaps in the 
> > "early_resume" stage) rather than calling them all in one chunk?
> >
> > 		Linus
> >   
> _WAK method is system-wide. Individual objects do not have their own 
> resume methods.
> One way of reordering internal ACPI resume is done in patch series to 
> 7122, I mentioned that earlier.
> It's possible to resume ACPI devices after execution of _WAK in pm->finish.

Does it solve the original problem where finish() was getting run after
device_resume(), and finish() was corrupting PCI register settings like
MSI?


-- 
Stephen Hemminger <shemminger@osdl.org>