Comment # 13 on bug 1175599 from Takashi Iwai

Thanks.  Through a quick glance between working and non-working cases, I see no
obvious problem.  The built-in keyboard is PS2 and it's recognized as
input/event0 in both cases.

Could you try to boot with the new kernel again, but with the boot option "3"?
This will stop the graphical mode, and you'll login on Linux console.  Check
whether the keyboard works there or not.

BTW, while testing different old and new kernels, better to keep disabling
Secure Boot mode.  It makes things much easier.