One note...  I'll double check, but on my XPS 13 9380, as I recall, I
have to manually disable autosuspend on all of the XHCI controllers
and internal hubs after running "powertop --auto-tune", or else any
external mouse attached to said USB device will be dead to the world
for 2-3 seconds if the autosuspend timeout has kicked in, which was
***super*** annoying.

						- Ted

Perhaps this was not XHCI controller in the system, but maybe external
one provided by ASMedia?  I've not heard anything similar for host system
yet.