Windows 7 Brightness Not working - Dell Precision - M4600/6600 nVidia Optimus

If you have Windows 7, a Dell Precision Laptop with nVidia Quadro 1000M or 2000M with Optimus enabled and your brightness is not working...add this registry key and restart.


Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0000]
"FeatureTestControl"=dword:0000ffff
"KMD_EnableBrightnessInterface2"=dword:00000000
"KMD_EnableBrightnesslf2"=dword:00000000

[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0001]
"FeatureTestControl"=dword:0000ffff

[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\intelkmd]
"FeatureTestControl"=dword:0000ffff