Hi -
I'm currently experimenting with some poor USB device
which receives the DCF77 timing signal. Final goal
is to get this fed into ntpd.

That device is completely misdesiged but relatively cheap --
one has to poll it through USB control transfers to get the
slopes of the timing signal. One can't expect an accuracy
better than 10ms (HZ)  that way, but that would be enough for
our application (remote data loggers).

Anyway, what my driver does is to issue these control
requests (usbd_do_request()) within a callout(9)
handler, and to stuff the result into a tty.

Now I'm getting a kernel diagnostic warning from tome to time:
WARNING: WANT PMAPLOAD ON SYSCALL ENTRY

Am I doing something illegal?

best regards
Matthias