Jon wrote:
i/o error and resulting 44-byte file of silence.
This indicates that the chip does not see any S/PDIF signal.
Can't you connect some S/PDIF output to an input for testing?
I'm wondering if this problem could be really just as simple as someone having guessed wrong about the correct value there having not had this particular model on hand to test with?
C-Media chips were very common once upon a time, and S/PDIF input always worked just fine for everybody else. There are no GPIOs, so the only possible hardware implementation is to connect the S/PDIF input directly to the chip's input pin(s).
The Windows driver for this board is the standard C-Media driver, so there isn't any additional hardware that needs to be programmed.
I don't know anything that could be done.
Regards, Clemens