INT 15 - Advanced Power Management Spec - ENABLE/DISABLE POWER MANAGEMENT
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: 155309

155308BXFFFF - Advanced Power Management Spec - ENABLE/DISABLE POWER MANAGEMENT