My PNLF: 
            Device (PNLF)
                    {
                        Name (_HID, EisaId ("APP0002"))
                        Name (_CID, "backlight")
                        Name (_UID, 0x0A)
                        Name (_STA, 0x0B)
			            Method (_BCL, 0, NotSerialized)
			            {
			                Return (\_SB.PCI0.PEGR.GFX0.LCDD._BCL ())
			            }
			            Method (_BCM, 1, NotSerialized)
			            {
			                \_SB.PCI0.PEGR.GFX0.LCDD._BCM (Arg0)
			            }
			            Method (_BQC, 0, NotSerialized)
			            {
 			               Return (\_SB.PCI0.PEGR.GFX0.LCDD._BQC ())
			            }
			            Method (_DOS, 1, NotSerialized)
			            {
			                \_SB.PCI0.PEGR.GFX0._DOS (Arg0)
			            }
                    }
I patched my dsdt the instructions on the first page, throw kext on kext utility... 
The sound is not regulated by the function keys. I use native kext for sound.