Compatibility: VGA
Expects: AH    12H
BL    00H
AL    subfn: 00H = prepare for adapter switching off
ES:DX => 128-byte buffer to hold state data
01H = prepare for system board video switching off
02H = switch off active video
ES:DX => 128-byte buffer to hold state data
03H = switch on active display
ES:DX => 128-byte buffer containing saved data
                                                                  
Returns: AH    12H if a valid value was passed in AL
                                                                  
Info: ON PS/2 systems, this provides a means to switch between the
built-in VGA (on the motherboard) and another, incompatible
display system.

See Also: INT 10H 12H (EGA/VGA Special Functions/Alternate Select)
- -

INT 10H 12H BL=35H: Switch PS/2 Displays