Int 10 Fn 4F10  - Vesa Vbe/pm (power Management) V1.0+ - Get Display Powe  [p]

   AX = 4F10h
   BL = 02h

Return: AL = 4Fh if function supported
   AH = call status
       00h successful
          BH = current power state (see #0088)
       else failed

See Also: AX=4F10h/BL=00h,AX=4F10h/BL=01h,AX=A00Dh