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

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Wed, Mar 06, 2013 at 07:29:34PM -0500, Konrad Rzeszutek Wilk wrote:
> > > 
> > > Actually the correct path is: /sys/firmware/acpi/tables/DSDT
> > > So the acpi tables are there.
> > > 
> > > .. but the problem is there's no _PCT info in them.
> > > 
> > 
> > .. so on which hardware is xen-acpi-processor driver required? 
> > 
> > Is the actual problem that I don't have _PCT because it's not 
> > required/supported on my hw,
> > and thus I don't need the whole xen-acpi-processor driver? 
> > 
> > I checked the Xeon 5600 CPU, and also Ivy Bridge i7, and there's no _PCT on 
> > either one..
> 
> I always forget which of _P* are important. I think _PPC, _PSS and _PCD
> are the crucial ones. The _PCT is the thermal one - which I think are usually
> found on laptops.
> 

I don't seem to have _PCT on my Ivy Bridge i7 laptop.. 

> In your case then .. lets go back to the start - the driver failed with -EIO
> and it was v3.4.x kernel? Now that I've figured out the regression with v3.9
> I can take a look at this.
> 

Ok.

So the problem for me with Linux 3.4.32 kernel is "modprobe xen-acpi-processor" 
fails:
initcall xen_acpi_processor_init+0x0/0x6b0 [xen_acpi_processor] returned with 
error code -5

The error deeper down in the ACPI internals is:
processor_perflib-0430 [00] processor_get_performa: ACPI-based processor 
performance control unavailable

Function call path is this:

xen_acpi_processor_init()
        acpi_processor_register_performance(perf, i)                    <-- 
returns -EIO
                acpi_processor_get_performance_info(pr)                 <-- 
returns -ENODEV and prints the error to dmesg
                        acpi_get_handle(pr->handle, "_PCT", &handle);   
                                acpi_ns_get_node()                      <-- 
doesn't find _PCT

        goto err_out;                                                   <-- 
modprobe xen-acpi-processor fails


The CPU in question is:
Intel(R) Xeon(R) CPU L5640

ACPI DSDT.dsl is here:
http://pasik.reaktio.net/dell-r510-acpi-dsdt.dsl

-- Pasi


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