I have a Macbook Pro 6,1 that I have dual booting OSX and now Fedora 15. I'm working on getting the audio working.
In System Settings > Sound > Output there are two options for audio devices:
High Definition Audio Control Digital Stereo (HDMI) Internal Audio Analog Stereo
There is no sound when the first option (HD Audio Control Digital Stereo) is selected. However, if the second (Internal Audio Analog Stereo) is selected the headphone jack works, but the on board speakers do not work.
I can't even tell what actual hardware on the laptop is. The Apple website (http://support.apple.com/kb/SP621) just says,
Stereo speakers with subwoofers, omnidirectional microphone, audio line in minijack (digital/analog), audio line out/headphone minijack (digital/analog)
How do I get the speakers working?