After installing Ubuntu and its derivatives on a Dell XPS Studio, both the headphone jacks are unusable. Plugging earphones into the jacks produces no sound, and the system still outputs the sound on the laptop's speaker.
This problem is confirmed to affect Ubuntu 10.04 (Lucid Lynx) up to Ubuntu 12.10 (Quantal Quetzal).
The problem is related to alsa and can be fixed with these steps.
$ sudo vi /etc/modprobe.d/alsa-base.conf
options snd-hda-intel model=dell-m6
$ sudo reboot
|Ubuntu 10.04 (Lucid Lynx)|
|Ubuntu 12.10 (Quantal Quetzal)|
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