Re: Regression: unable to boot after commit bd9240a18edf ("x86/apic: Add TSC_DEADLINE quirk due to errata") - Surface Pro 4 SKL

[Zhang Rui]

On Tue, 2017-11-28 at 10:34 +0100, Thomas Gleixner wrote:
> On Tue, 28 Nov 2017, Zhang Rui wrote:
> 
> > 
> > On Tue, 2017-11-28 at 09:14 +0100, Peter Zijlstra wrote:
> > > 
> > > On Tue, Nov 28, 2017 at 10:08:53AM +0800, Zhang Rui wrote:
> > > > 
> > > > 
> > > > Hi, All,
> > > > 
> > > > My Surface Pro 4 is unable to boot after 4.12. The symptom is
> > > > that
> > > > kernel freezes during boot, and the last message in the screen
> > > > is
> > > > loading the initrd image. And I have bisected it to this commit
> > > > 
> > > > +//	DEADLINE_MODEL_MATCH_REV (
> > > > INTEL_FAM6_SKYLAKE_MOBILE,	
> > > > 0xb2),
> > > And what microcode version do you run? Have you installed the
> > > latest
> > > microcode package and updated your initrd to include it? My
> > > skylake
> > > is
> > > running 0xba.
> > No, I didn't upgrade my microcode.
> > 
> > $ cat /proc/cpuinfo
> > ...
> > processor	: 0
> > vendor_id	: GenuineIntel
> > cpu family	: 6
> > model		: 78
> > model name	: Intel(R) Core(TM) i7-6650U CPU @ 2.20GHz
> > stepping	: 3
> > microcode	: 0x9e
> > ...
> > 
> > I suppose the problem should be gone if I upgrade the microcode.
> > But the real problem to me is that the system FREEZES after kernel
> > upgrade.
> Confused. So the match disables the deadline timer due to 0x9e <
> 0xb2. And
> not having deadline timer makes the boot fail despite the fact that
> deadline timer is borked with microcode < 0xb2.
> 
> Can you verify by adding 'lapic=notscdeadline' to the command line of
> a
> 'working' kernel? That should cause a freeze as well then.
> 
yes. Tried 4.4 distro and 4.12 vanilla kernel, kernel always freezes
with boot option "notscdeadline"/"lapic=notscdeadline".

thanks,
rui

> Thanks,
> 
> 	tglx