In Ubuntu 12.04 laptop when you plugged in headphones, sounds may come out from both headphones and speakers. Here is a solution:
- Open terminal from the dash home or press Ctrl+Alt+T, add the ppa:
sudo apt-add-repository ppa:ubuntu-audio-dev/alsa-daily
- update the source:
sudo apt-get update
- Install alsa-hda-dkms package:
sudo apt-get install alsa-hda-dkms
Reboot and see effect!