Hello,
the internal mic of my Dell Vostro 3500 was not working with kernel v3.2-rc1 (and propably with none of the older kernels).
By choosing dell-s14 as the model I was able to get the internal mic working, but now my externel mic jack was a second headphone out jack. So I looked at the differences between the pin configurations of the auto model and the dell- s14 model and found out, that setting the value of on 0x11 from default 0x400000f6 to 0x90a60160 was responsible for the working internal mic.
I attached a patch that fixes this problem but it has a flaw. Since I did not know what value I have to put in the second argument of SND_PCI_QUIRK I put 0x0000 as dummy in there. It works for me but if anyone could give me a hint on how to obtain, what I really have to put in there, I would be happy to fill in the right value.
With best regards Julian Wollrath