Ubuntu 12.04; linux-kernel 3.2.0-27; alsa driver ver. 1.0.24 i have some problem with my HDA Intel ALC662 rev1. When i unmuting front mic in alsamixer, noise appear in my speakers in rear panel, but anyone devices is not plugged in in front panel. Besides in pulseaudio-control panel in hardware properties my device set to analog stereo duplex, and i can't set it to analog stereo output beacouse it's always set back to stereo duplex.
Setting the soundcard profile was limited in gnome-control-center for a simpler user experience (see bug #972554). This also affects the switching to
Analog stereo from
Analog duplex stereo. We can still do this with pavucontrol . This may also improve the noise you are experiencing when no device is plugged in the input jack.
From the log files attached to bug #1027570 we can see that we try to switch to the microphone port but fail. We may disable the automatic switching by commenting out the following line in
/etc/pulse/default.pa to look like this:
# load-module module-switch-on-port-available
This requires editing this file as root (e.g. by running
gksu gedit /etc/pulse/default.pa). To take effect we need to restart pulseaudio with
If that does not help please remove the
# again to re-enable switching audio to a new audio port when it becomes available.