I have a MacBook Pro 4th generation (Penryn) and using Ubuntu 8.04 all was  perfect!

Two days ago I upgraded the operating system to Intrepid Ibex (8.10), and after some hour downloading the packages and installing them, the new Ubuntu was running on my MacBook… But also some problems war running as well! Ubuntu has some audio problem (no sound at all!!) on MacBook Pro…

The sound card is the Hda-Intel and the kernel module is the snd-hda-intel. The solution? After some search on the net, I found that: help.ubuntu.com

Here the solution (very easy, really):

1. Open the file /etc/modprobe.d/options (you need to be root)

sudo gedit /etc/modprobe.d/options

2. Add the following line at the end of the file

options snd_hda_intel model=mbp3

3. If you have changed /etc/modprobe.d/alsa-base previously, adding something similar to the previous line, comment it.

4. Reboot (mute your microphone before doing that, or your ears will implore pity!)