No SPDIF output on 3993d for FreeBSD 5.4

[Guest]

After upgrading oss to 3993d from 3993c, SPDIF output results in an Input/output error. The following lines appear in my dmesg output when osstest attempts to play to /dev/dsp2 (SPDIF):

Interrupt storm detected on "irq7: oss"; throttling interrupt source
OSS ICH: Output timed out
oss: Output timed out (sync) on device 2

The system is running 5.4-STABLE as of Jan 14, 2006. The soundcard is the onboard NVidia nForce 2 hardware found on the ASUS A7N8X mainboard.

Is there any debugging code that I can enable to provide more useful diagnostic information?

Any assistance or recommendations will be very much appreciated.

Thank you,

~brian