As per post #6, read here:
http://www.insanelymac.com/forum/to...udio-voodoohda-and-applehda-at-the-same-time/
But since it relies on editing Info.plist matching for VoodooHDA to allow AppleHDA to match against HDAU, and VoodooHDA against HDEF, it does not apply to your hardware. Your hardware has only HDEF, no separate HDAU (separate HDAU/HDEF only used on Haswell and Broadwell). Which means you cannot use a separate kext for onboard audio vs. HDMI/DP audio.
You need to pick one audio method... and you cannot mix AppleHDA with VoodooHDA.