Int 6F Fn 0402  - Hp Vectra Ex-bios - "f_io_ctrl Sf_unlock" - Release Sub  [b]

   AX = 0402h
   BP = driver ID (see #3412)
   DH,DL = major,minor address (optional)

Return: AH = status (see #3415)
   BP,DS destroyed
Desc:  release specified sub-addresses from exclusive access

Note:  this function is documented as present but unsupported in the drivers
     V_LTABLET, V_LPOINTER, and VLTOUCH

See Also: AX=0200h"HP Vectra",AX=0400h"SF_LOCK"