hardware during resume operations where a value can be set that will
survive a reboot.
+pm_trace is not compatible with asynchronous suspend, so it turns
+asynchronous suspend off (which may work around timing or
+ordering-sensitive bugs).
+
Consequence is that after a resume (even if it is successful) your system
clock will have a value corresponding to the magic number instead of the
correct date/time! It is therefore advisable to use a program like ntp-date