Issue a power management request to a given device. The
PM_SUSPEND and PM_RESUME events are handled specially. The
data field must hold the intended next state. No call is made
if the state matches.
Calling pm_send directly is not generally recommended, in paticular there is no locking against the pm_dev going away. The caller must maintain all needed locking or have 'inside knowledge' on the safety. Also remember that this function is not locked against pm_unregister. This means that you must handle SMP races on callback execution and unload yourself.