hdajackretask on Linux does that, part of alsa-tools. Blog post by author from 2011: http://voices.canonical.com/david.henningsson/2011/11/29/turn-your-mic-jac

hdajackretask on Linux does that, part of alsa-tools. Blog post by author from 2011: http://voices.canonical.com/david.henningsson/2011/11/29/turn-your-mic-jack-into-a-headphone-jack/ http://voices.canonical.com/david.henningsson/2011/11/29/tur... I believe similar utilities exist on Windows at least with some cards.