Comment 3 for bug 1603696

E555, same chip, same problem.
This guy too:
https://askubuntu.com/questions/585709/headphones-not-recognized/674501
This one too, but got it fixed using the right "model":
http://www.linuxquestions.org/questions/slackware-14/slackware64-on-lenovo-g50-70-no-sound-4175514003/
and here too (but managed to solve it):
https://bbs.archlinux.org/viewtopic.php?id=224771
Same chip, but opposite issue (sound in the headphone only);
https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/1654857