Int 15 Fn 5308  - Advanced Power Management Spec - Enable/disable Power M  [p]

   AX = 5308h
   BX = FFFFh
   CX = new state
       0000h disabled
       0001h enabled

Return: CF clear if successful
   CF set on error
       AH = error code (01h,09h,0Ah) (see AX=5300h)

Notes: when power management is disabled, the system BIOS will not
     automatically power down devices, enter stand-by or suspended mode,
     or perform any power-saving actions in response to AX=5305h calls
   should not be called from within a hardware interrupt handler to avoid
     reentrance problems

See Also: AX=5309h