I used Mirone's AppleHDA for ALC255 with every working except external mic. It seems the patched AppleHDA kext do not have external mic information. So nothing happens when I insert headphone into the jack. The computer always use internal mic as the only input source. I tried to patch external mic myself but without success. Any help would be appreciable.
p.s. my PC has single jack for both mic and headphone.