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
