Just a follow-up thought: The mechanical clicking noises that the sound card produces are apparently caused by a relay on the card. I wonder if the driver isn't getting the state of the relay?
Also, I've located the FreeBSD equivalent driver for comparison. I'm no C programmer, so I don't know whether this is useful. This driver only appears support up to the predecessor model. FreeBSD driver: https://github.com/polachok/xonar-freebsd
