K 10
svn:author
V 6
kevans
K 8
svn:date
V 27
2019-12-31T13:56:48.953164Z
K 7
svn:log
V 148
psm: properly check for atkbdc_open failure

atkbdc_open can return NULL if the unit's out of bounds or the softc isn't
setup. Check it to be safe.

END