Ubuntu 16.04: screen unlock fails if my phone is plugged in?

[Paul Smith]

On Fri, 2017-03-03 at 16:20 +0000, Grizzly wrote:
> Any chance you setup Pam to use that phone as a key?

Not knowingly, for sure :).

I have no idea how to do that, or to check whether it has been done.

And it can't be required because my screen unlocks fine without my
phone plugged in.  Also my phone doesn't wake up when I try to unlock
my screen.