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Re: [Xen-devel] Kernel crash with acpi_processor, cpu_idle and intel_idle =y

On Tue, Jul 31, 2012 at 01:58:48PM +0200, Mark van Dijk wrote:
> Message 501657C70200007800091357@xxxxxxxxxxxxxxxxxxxx contained:
> >The first thing intel_idle_init() does is check
> >boot_option_idle_override, and I thought this got forced to
> >something other than IDLE_NO_OVERRIDE by the Xen code.
> >But at least in the current kernel that doesn't seem to be
> >the case anymore, and thus I suppose that it's dying on the
> >subsequent
> >
> >     retval = cpuidle_register_driver(&intel_idle_driver);
> >     if (retval) {
> >             printk(KERN_DEBUG PREFIX "intel_idle yielding to %s",
> >                     cpuidle_get_driver()->name);
> >             return retval;
> >     }
> >
> >since cpuidle_get_driver() is presumably returning NULL (after
> >all xen_arch_setup() does call disable_cpuidle()).
> This is way beyond my knowledge. I'm no programmer so unfortunately I
> can't say anything about it.
> Not using INTEL_IDLE is no problem, in fact, I now understand that
> INTEL_IDLE is not (should not) even used with Xen.

Sure, but it should be smart enought not to crash. Can you please try the
patch I sent in the other email.
> But I have to ask whether we can look at the other issue a bit more,
> regarding CPU states and how I can get states C4-C7 to work.

You seem to be using MWAIT states, which is what the C4-C7 are.
> Perhaps you can tell me whether the BIOS options "ACPI T-state",
> "C3 Auto Demotion" and "C1 Auto Demotion" should be disabled. I think
> they should be, as I read it this sets respectively C4-C7 to C3, and
> C3-C2 to C1 right? I have (and had) those disabled, when I enabled them
> the output from xenpm did not differ.

I am not sure what those do. What did the manual say that they are doing?

BTW, C4-C7 are basically C3 states with MWAIT - and from your pastebins
you seem to have those enabled.

> Much obliged,
> Mark.
> -- 
> Stay in touch,
> Mark van Dijk.              ,--------------------------------
> ---------------------------'        Tue Jul 31 11:28 UTC 2012
> Today is Boomtime, the 66th day of Confusion in the YOLD 3178

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