No sound from "out" jack on a Gigabyte z77x-dh5h motherboard

[Alexandre]

I'm pasting here the bug report initially posted on bugs.kde.org (bug #299578), as it seems it should be reported upstream, specifically to David Henningsson.

Using a Gigabyte z77x-ud5h motherboard, you can only hear sound when plugging a jack cable in rear, c/sub or side jack, but not if it's in the usual green "out" one.
Having tried all the output profiles without success, I guess that's a bug.

Reproducible: Always

Steps to Reproduce:
1. Plug the jack cable into the "out" jack (the green one on that motherboard)
2. Play something in clementine for instance
3. No sound output
4. Plug the jack cable into the "rear", "c/sub" or "side" jack to get sound

Actual Results:
No sound heard when jack plugged in "out"

Expected Results:
Hear sound when jack plugged in "out"

Additional info :
# lsb_release -rd
Description: Ubuntu 12.10
Release: 12.10
# apt-cache policy pulseaudio
pulseaudio:
  Installé : 1:2.1-0ubuntu4
  Candidat : 1:2.1-0ubuntu4
  Table de version :
 *** 1:2.1-0ubuntu4 0
        500 http://fr.archive.ubuntu.com/ubuntu/ quantal/main amd64 Packages
        100 /var/lib/dpkg/status