On Tue, Nov 28, 2017 at 04:22:15PM +0800, 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.
Yes, that is weird and unexpected. The patch basically kills TSC_DEADLINE usage on older microcode. This makes the kernel then use the old LAPIC timer mode. Does your machine boot with "notscdeadline" ? Which _should_ be the same.
