I've got Dell Vostro 3360 laptop, and internal mic doesn't work. I use 3.8 series kernel.
When I try to record sound from mic I get only weird noise. All sliders in alsamixer are 100% and capture is ON.
alsa-info.sh script output could be found here.
I guess it could be fixed by specifying model for snd-hda-intel module but I've got no idea what model I should specify.