Comment # 8 on bug 964562 from Takashi Iwai

(In reply to Hot MusicFan from comment #5)
> (In reply to Takashi Iwai from comment #4)
> > Did you try to boot with xhci_hcd.quirk option I suggested?
> 
> Like this? (attachment below)

Note that you can edit the boot option directory in GRUB by pressing 'e' key.

And do I understand correctly that your machine *reboots* after shutdown
automagically?

For a spurious reboot, another possible source is Wake-on-LAN.  This can be
disabled via ethtool command on the fly.