Comment 62 for bug 141445

Possible path for a work around:

I have a Toshiba P1620 using the Realtek ALC262 chipset

In Jaunty (Ubuntu 9.04 AMD64) the following actions fixed the issue:

Went to the Realtek web page and downloaded the latest Alsa driver package 1.0.21
Installed a new compiler at the suggestion of a "how to" web page
Installed the upgraded the Alsa packages ( sudo ./configure, sudo make, sudo make install etc)
As admin edited /etc/modprobe.d/alsa-base.conf to add the following line at the end : options snd-hda-intel model=auto ( somehow only the auto option allows the system to find the mic)
rebooted
opened a terminal session ran alsamixer and unmuted all microphones and changed the input from "Int mic" to "front mic"
changed all sound applications to use Alsa instead of Puls Audio

Following these steps everything works fine, the internal mic is functional although a bit muffled

In Karmic (Ubuntu 9.10 AMD 64) things get a bit ugly so far:

The Karmic upgrade from canonical installs ALSA 1.0.20
I reinstalled the ALSA packages 1.0.21
Changed the Alsa-base.conf line
ran alsamixer and there is the problem:

No matter what I tried so far the system assigns the default sound card to Pulseaudio ! In alsa mixer however one can select manually the hda-intel card, this enables the microphone which sound perfectly clear compared to the fix in 9.04.
However, at the next reboot the system will default back to Pulse audio which does not handle the microphone.

So far I have not found a way to disable PulseAudio and have the system use Alsa instead. At this point I am considering reinstalling an earlier version of Ubuntu.

Let me you if you guys have a fix on how to have Alsa handle all audio in Karmic

Cheers!