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

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Sun, May 12, 2013 at 07:51:26PM +0300, Pasi Kärkkäinen wrote:
> On Mon, Mar 18, 2013 at 04:20:51PM -0400, Konrad Rzeszutek Wilk wrote:
> > > 
> > > Hmm, on the R510 server where xen-acpi-processor doesn't work 
> > > /sys/firmware/acpi/tables/dynamic/ is empty.. 
> > 
> > Pfff.. And 'cpuinfo' or 'cpufreq-info' when you boot baremetal gives
> > you different P-states?
> > 
> > If so, is the DSDT different that when running under Xen? And
> > lasty, does it create any SSDT in the dynamic directory?
> >
> 
> Finally I figured this one out.. in the end it was a BIOS 
> settings/configuration issue.
> 
> I found this: 
> http://en.community.dell.com/techcenter/power-cooling/w/wiki/best-practices-in-power-management.aspx
> 
> So I had to enable "OS Control" for "Power Management" in the Dell server 
> BIOS,
> and after that the CPU P-states are available in the ACPI tables, 
> and xen-acpi-processor driver loads and works OK in the dom0 kernel!

Aah, right. That would explain it.
> 
> (I'm almost 100% certain I tried that option already earlier,
> so I don't have any idea why it didn't work back then.. but *now* it seems to 
> work!)
> 
> For reference I'm using Intel L5640 Xeon CPU, and here's xenpm output for it:
> 
> # xenpm get-cpufreq-states
> 
> cpu id               : 0
> total P-states       : 7
> usable P-states      : 7
> current frequency    : 1596 MHz
> P0         [2262 MHz]: transition [                   5]
>                        residency  [                  59 ms]

Woot! Turbo Mode!

> P1         [2261 MHz]: transition [                   0]
>                        residency  [                   0 ms]
> P2         [2128 MHz]: transition [                   0]
>                        residency  [                   0 ms]
> P3         [1995 MHz]: transition [                   0]
>                        residency  [                   0 ms]
> P4         [1862 MHz]: transition [                   0]
>                        residency  [                   0 ms]
> P5         [1729 MHz]: transition [                   0]
>                        residency  [                   0 ms]
> *P6        [1596 MHz]: transition [                   5]
>                        residency  [                3437 ms]
> 
> cpu id               : 1
> total P-states       : 7
> usable P-states      : 7
> current frequency    : 1596 MHz
> P0         [2262 MHz]: transition [                   4]
>                        residency  [                 103 ms]
> P1         [2261 MHz]: transition [                   0]
>                        residency  [                   0 ms]
> P2         [2128 MHz]: transition [                   0]
>                        residency  [                   0 ms]
> P3         [1995 MHz]: transition [                   0]
>                        residency  [                   0 ms]
> P4         [1862 MHz]: transition [                   0]
>                        residency  [                   0 ms]
> P5         [1729 MHz]: transition [                   0]
>                        residency  [                   0 ms]
> *P6        [1596 MHz]: transition [                   4]
>                        residency  [                5893 ms]
> 
> .. and so on.
> 
> 
> Thanks a lot Konrad for your help on this!

Sure thing, thought you found the resolution so the credit is due you.
> 
> 
> -- Pasi
> 

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