yes you need to add code for DTGP you can find the complete document at this link here

download the file "How_to_patch_DSDT_with_LAN_and_HDEF_functions_inc luding_LegacyHDA.zip"

follow the steps in that doc but you have to use the code from my post for codec id and layout ID. everything else is the same.

For our board codec and layout ID:

"codec-id",
Buffer (0x04)
{
0x89, 0x08, 0xEC, 0x10
},

"layout-id",
/**** Is ResourceTemplate, but EndTag not at buffer end ****/ Buffer (0x04)
{
0x79, 0x03, 0x00, 0x00
},

and use the appleHDA in my post reboot and your should be good to go.

BTW I didnt do the LAN Part of the patch you can try if you want.