I installed Ubuntu 14.04.1 onto my MacBook Pro Core Duo 17“ (MacBookPro1,2). For reference, you can determine your system identifier inside of Ubuntu with the following command:

sudo dmidecode -s system-product-name

After I installed Ubuntu, I noticed the sound didn't work. This is actually a fairly common issue with the snd-hda-intel module and is described here. The page claims the information is out of date, but it's still helpful.

I'll repeat the steps here just in case. To solve the problem:

• Determine the model of the sound card.
  • cat /proc/asound/card0/codec* | grep Codec
  • In the case of my MacBook Pro, this command returned: “Codec: SigmaTel STAC9221 A1”
• Find the “model” option to use for your model of the sound card.
  • zcat /usr/share/doc/alsa-base/driver/HD-Audio-Models.txt.gz | less
  • Find your model and see the various available options for the models.
• Decide which option you want to use, and stick it into /etc/modprobe.d/alsa-base.conf
  • For example, on my MacBook Pro, I added the following line to the bottom of the file:
  • options snd-hda-intel model=macbook-pro-v1
• Reboot. The instructions at the linked page say you can run a command to reload alsa, but it didn't work for me until I rebooted.
• If it still doesn't work, try another option until you find one that works.