INT 10 - VIDEO - ALTERNATE FUNCTION SELECT (PS, VGA) - VIDEO REFRESH CONTROL
        AH = 12h
        BL = 36h
        AL = new state
            00h enable refresh
            01h disable refresh
Return: AL = 12h if function supported
Desc:   specify whether the contents of video memory should be displayed on
          the screen; disabling refresh effectively blanks the screen
SeeAlso: AX=BF05h

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