On Tue, 2008-01-29 at 12:58 -0600, Marzan, Richard non Unisys wrote:
> I tried googling around but no helpful content so far. I have a laptop
> with built-in sound. It uses the HDA_intel kernel module. My problem is
> that I can't silence the onboard/built-in speakers when I plug in the
> headphones to the machine. Muting sound would lead to all jacks and
> audio ports to be silenced -- not just the built-in speakers, which I
> intend to mute solely leaving sound alive on the headphone jacks. There
> are no channels readily observable to differentiate where sound goes and
> to which port with alsa-mixer. The behavior I would like to achieve is
> one that will allow me to mute onboard speakers while continuing to have
> the headphones receive audio signals. Has anyone ever done this? Any
> pointers to documentation will be appreciated. 

Does it work with Windows? I'd expect such things to be implemented in
hardware.