[Alsa-user] no sound on built-in speaker but headphone is OK

[derek c. <der...@gm...>]

I installed Mint 15 on my Macbook Air 1,1 and there's no sound from
built-in speaker. Although there are many similar topics discussed on
Internet but none of the solutions work for me. Here is the info collected
by alsa-info.sh

 http://www.alsa-project.org/db/?f=d2dab430e40353890b8fc98540a8380cf051bc71.


While searching the solutions, I found Realtek provides their ALSA driver
which seems newer than the version I installed. It's a pity that the result
is worse. I got no sound either from built-in speaker or headphone. This is
the info with Realtek's driver

  http://www.alsa-project.org/db/?f=1f563569b05012c4eff8a75ec5712400c9a3c46d
.

I'm interested to know what the difference is between these two logs and
how I can fix my problem on built-in speaker.

Thanks,
Derek