Comment 6 for bug 784440

I'm also experiencing this issue in 12.04 on my macbook pro. If I look at alsamixer, the headphones volume is always reset to 100% if the volume is changed with the gnome volume control.

I noticed that if I open up the sound settings, and I change "connector" to "speakers", the headphone level will stay where I set it in alsamixer (and I can still hear audio from the headphones, and not the speakers).