await & asleep

[Norbert Koch]

Hello.

The functions await() and asleep() in kern_synch.c
are marked as EXPERIMENTAL/UNTESTED.
Is this comment still valid? Does anyone have used
those functions successfully? Should I better not
use them in my device driver code for RELENG_4?
How do I correctly cancel a request (as I should do
according to the man page): "asleep (NULL, 0, NULL, 0)"?

Any help appreciated.

Norbert