Re: ION and HDMI/Optical Audio
Yes, I compile my own kernels. Although you should be okay with a pre-made kernel as long as the Nvidia HDMI driver is included (just a guess). If you're using the driver as a module, then you'll need to add options snd-hda-intel model=3stack-dig to your /etc/modprobe.d/alsa-base.conf file. Assuming that model setting is correct for your mainboard. Otherwise you'll need to adjust it accordingly.