Is there always trouble, or only when docked or after a suspend/resume cycle? Can you hear sound through headphones? Does fiddling with any of the knobs in alsamixer help? (You may have to press F6 first to make sure you are setting the controls for the ALSA device rather than pulseaudio.)
Thank you Jonathan, yes i notice the trouble is *only* with "dock lineout" and kernel 3.2. No problem with "integrated loudspeaker" or "laptop lineout". I also test kernel 3.3rc2 and is fine with "dock lineout", "integrated loudspeaker" and "laptop lineout" Guy