I'm doing exactly the same. I think it might be a hardware failure, not software or drivers.
I've just plugged only part of an old mobile headphones.
I hope I can upload a picture of it so you can see it. It works fine with "that" plugged in.
My notebook model is DV6-6186nr and I'm from Uruguay, South America, and bought it here in June 2012.
Thanks for your reply !! We'll keep on waiting for any HP Solution, then.
