Comment 3 for bug 733236

Ubuntu 11.04, i386: Not fixed!

WORKARROUND from CLI:

1) find ALSA control for HEADPHONE SENSE (it is 26 at NC4200, 32 at NC6000, etc):

nc4200$ amixer controls | grep -i sense
numid=26,iface=MIXER,name='Headphone Jack Sense'
numid=27,iface=MIXER,name='Line Jack Sense'

2) Activate 'Headphone Jack Sense':

nc4200$ amixer cset numid=26 on
numid=26,iface=MIXER,name='Headphone Jack Sense'
  ; type=BOOLEAN,access=rw------,values=1
  : values=on

3) Store ALSA configuration (to file/var/lib/alsa/asound.state):

nc4200$ sudo alsactl store

And the problem is fixed! Not difficult but I was searching this trick for several weeks...