Int 10 Fn 4F07  - VESA SuperVGA BIOS V1.1+ - Get/set Display Start         [V]

   AX = 4F07h
   BH = 00h (reserved)
   BL = function
       00h set display start
       CX = leftmost displayed pixel in scan line
       DX = first displayed scan line
       01h get display start

       Return: BH = 00h
           CX = leftmost displayed pixel in scan line
           DX = first displayed scan line

Return: AL = 4Fh if function supported
   AH = status
       00h successful
       01h failed

Note:  this function is valid in text modes, provided that values are
     multiplied by the character cell width/height

See Also: AX=4F01h,AX=4F05h,AX=4F06h