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.
Thanks,
tglx
