When apm cannot open /dev/apm, the error message does not give clues as to why it cannot open the device. Fix: Apply this patch to /usr/src/usr.sbin/apm/apm.c How-To-Repeat: I didn't have apm enabled in the kernel. However, this was not obvious from the error message.
State Changed From-To: open->closed Fixed by green in revision 1.22 of apm.c. Thanks.