Sony Vaio VPCZ12 DSDT hybrid graphics info

The Sony Vaio VPCZ12 model comes with a ACPI DSDT table that has two methods to allow for switching on/off the discrete graphics card:
_SB.PCI0.P0P2.DGPU._ON
_SB.PCI0.P0P2.DGPU._OFF


                                If (LEqual (_T_0, 0x03))
                                {
                                    Store (0xA003, P80H)
                                    Increment (CNTD)
                                    If (LEqual (And (Arg3, 0x03), Zero))
                                    {
                                        Return (^^P0P2.DGPU._STA ())
                                    }

                                    If (LEqual (And (Arg3, 0x03), One))
                                    {
                                        ^^P0P2.DGPU._ON ()
                                        Return (One)
                                    }

                                    If (LEqual (And (Arg3, 0x03), 0x02))
                                    {
                                        ^^P0P2.DGPU._OFF ()
                                        Return (Zero)
                                    }
                                }