This unit is non-functional with ALSA at the current moment (v1.023) despite the kernel modules needed (snd_hda_intel + snd_hda_codec_ca0110) being present. ALSA detects the sound card and it appears in /proc/asound/cards but no sound comes out and any application that outputs sound freezes.

OSS4 (4.2-rc1) does sort of work with the card. ossdetect detects the card, loads the correct kernel module, and osstest produces sound. OSS4 is a pain to get to work with current Linux distributions and flat-out does not work with KDE4. Any user application that can directly call on the /dev/dsp nodes like Mplayer only sporadically plays sound. Playing an audio file with Mplayer requires seeking around in the audio file a few times before sound starts playing. I was not willing to deal with this and returned the card for one that worked properly with ALSA.

The version of Ubuntu I am using recognizes the Creative Sound Blaster Extreme X-Fi card and sounds very nice. You can select either the digital output or the analog output. The system does not disable the internal audio so that is cool to be able to pick. Not a huge upgrade from the motherboard card (I am using an MSI MS-7680 with an Intel I-3 2100 CPU). I wanted to add a front panel jack and a digital output to my home stereo unit which the card was able to handle well. (The card has back output jacks for optical sound and a board connector that I hooked to a Frontx panel.)

There are some features that the Windows software version of the board would use but I have not found a way to tap into that yet. There is a newer version of this board so you can find them at low cost if you look around as I did.