Re: [Xen-devel] Linux 3.4 dom0 kernel error loading xen-acpi-processor: Input/output error

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Fri, Mar 15, 2013 at 05:15:18PM -0400, Konrad Rzeszutek Wilk wrote:
> On Fri, Mar 15, 2013 at 09:37:06PM +0200, Pasi Kärkkäinen wrote:
> > On Fri, Mar 15, 2013 at 05:19:34PM +0200, Pasi Kärkkäinen wrote:
> > > 
> > > > I need to look back at my notes on how the _PCT, _PSS, _Pwhatevername
> > > > work.
> > > >
> > > 
> > > Yep. Does xen-acpi-processor driver load OK on your servers? 
> > > 
> > 
> > I just tried Linux 3.8.3 as dom0 on the Xeon 5600 CPU and 
> > xen-acpi-processor fails 
> > in the same way as it fails with Linux 3.4.
> > 
> > I also tested on my Ivy Bridge i7 desktop, and there xen-acpi-processor 
> > driver loads OK..
> 
> And when I add some extra printks in working box I see that these calls:
> 
>       acpi_get_handle(pr->handle, "_PCT", &handle);
>       acpi_get_handle(pr->handle, "_PSD", &handle);
>       acpi_get_handle(pr->handle, "_PSS", &handle);
> 
> work, yet in the SSDT and DSDT those strings don't show up?
>

That's weird.. then again it probably explains why I didn't see 
those strings either in SSDT/DSDT on the i7 boxes.

> I think this
> requires some deep ACPI sorcery to figure out. On the AMD boxes they
> nicely show up.
>

Yeah I was afraid of that ;)

I've already tried simple things with acpi.debug_level=0xffffffff and 
acpi.debug_layer=0xffffffff
but nothing obvious so far.. I need to dig deeper..

It'd help to understand how all that SSDT/DSDT and PCT/PSD/PSS stuff is 
supposed to work.. 
If you happen to have good links to read about this ACPI black magic let me 
know (I'll probably regret asking for this ;)

-- Pasi


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