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Message-ID: <1511966690.2750.9.camel@intel.com>
Subject: Re: Regression: unable to boot after commit bd9240a18edf
 ("x86/apic: Add TSC_DEADLINE quirk due to errata") - Surface Pro 4 SKL
From: Zhang Rui <rui.zhang@intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
        LKML <linux-kernel@vger.kernel.org>, linux-x86 <x86@kernel.org>,
        Len Brown <len.brown@intel.com>, "Chen, Yu C" <yu.c.chen@intel.com>
Date: Wed, 29 Nov 2017 22:44:50 +0800
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On Tue, 2017-11-28 at 13:36 +0100, Peter Zijlstra wrote:
> On Tue, Nov 28, 2017 at 06:59:01PM +0800, Zhang Rui wrote:
> > 
> > > 
> > > > 
> > > > > 
> > > > > > 
> > > > > > My Surface Pro 4 is unable to boot after 4.12. The symptom
> > > > > > is
> > 
> > yes. Tried 4.4 distro and 4.12 vanilla kernel, kernel always
> > freezes
> > with boot option "notscdeadline"/"lapic=notscdeadline".
> Then for some mysterious reason, your Surface thing has a borked
> LAPIC.
> 
I agree. But however, on this platform, forcing a cpu microcode upgrade
after upgrading kernel does not seem like a good solution to users.
Thus I still like to dig into the problem further to see if we can
workaround this "regression" in software.
As the kernel freezes at a very early stage, do you have any advice on
how to narrow down the problem?

thanks,
rui