Compaq TRU64 AA-RNG2A-TE - Manual (Page 137)

If the user sets media that the card does not have, the interface may
not work.
9 Selects the new mode.
10 Resets the device to pick up the new mode (if the interface was running).
11 The default case returns an error that indicates that the caller has
issued an invalid ioctl command.
12.17 Releasing the Simple Lock and Resetting the IPL
The following code shows how the el_ioctl( ) routine releases the simple
lock and resets the IPL:
if (lock_on) { 1
simple_unlock(&sc->el_softc_lock);
splx(s);
}
return (status); 2
}
1 If the simple lock is still held, calls the simple_unlock( ) routine.
2 Returns the status of the ioctl request.
Implementing the ioctl Section 12–13