I have a Thinkpad X40 with 82801DBM (ICH4-M) audio chip and AD1981B codec, exactly the same hardware as on R51.
I had to switch off (mute) the "headphone jack sense" before I got sound on Feisty, too. The switch is readily available on alsamixer terminal app, but you have to explicitly enable it from Gnome Volume control preferences.
I have a Thinkpad X40 with 82801DBM (ICH4-M) audio chip and AD1981B codec, exactly the same hardware as on R51.
I had to switch off (mute) the "headphone jack sense" before I got sound on Feisty, too. The switch is readily available on alsamixer terminal app, but you have to explicitly enable it from Gnome Volume control preferences.
Thanks for the tip, Henning.