I just bought a new Lenovo P580 Ideapad yesterday and installed 12.04 64bit on it. I tried making a call with it and discovered that the built-in microphone wasn't working. I unmuted it in sound settings, and still nothing.
I did the following
:~$ cat /proc/asound/card0/codec#* | grep Codec Codec: Conexant CX20590 Codec: Intel PantherPoint HDMI
Followed some tips and ran
:~$ sudo gedit /etc/modprobe.d/alsa-base.conf
then added this to the end
options snd-hda-intel model=asus
I amplified the input sound with alsamixer to make sure... When the input was amplified to max on alsamixer, the input signal was at a constant level (1/3 of max) which I'm guessing was the system's noise. This played back was a low frequency hum. I plugged in headphones that have a built-in mic and that worked, although it still had the humming in the background.
I changed the last line in alsa-base.conf to:
options snd-hda-intel model=thinkpad
which gave me the same result.
I'm not sure where to go from here, and any help would be greatly appreciated...