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Date: Mon, 17 Dec 2012 15:02:38 +0100
From: Ingo Molnar <mingo@kernel.org>
To: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de>
Cc: Yinghai Lu <yinghai@kernel.org>, linux-kernel@vger.kernel.org,
        Borislav Petkov <bp@alien8.de>,
        Suresh Siddha <suresh.b.siddha@intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [regression] 3.7 ends in APIC panic
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* Bernd Schubert <bernd.schubert@itwm.fraunhofer.de> wrote:

> On 12/16/2012 07:07 PM, Yinghai Lu wrote:
> >On Sun, Dec 16, 2012 at 10:01 AM, Bernd Schubert
> ><bernd.schubert@itwm.fraunhofer.de> wrote:
> >>>can you post your .config for v3.7 ?
> >>>
> >>>wonder if you have x2apic in .config
> >>
> >>Which setting is it? Config is attached.
> >
> >your config does not have
> >
> >CONFIG_X86_X2APIC=y
> >
> >set.
> >
> >please enable that.
> >
> >your BIOS pre-enable x2apic somehow, so you must have x2apic enabled in kernel.
> >
> >it x2apic really can not be re-enabled by kernel, kernel would disable
> >x2apic automatically.
> 
> The system boots fine with x2apic enabled.
> 
> Thanks a bunch for your help,

I suspect this needs to be fixed/improved: currently it's way 
too easy to disable x2apic support accidentally.

Thanks,

	Ingo