OSS run also had interruption problems. It ran until: wave.c:657:Playing 1 second 440Hz tone at 8000x 8x2 WAVE_FORMAT_PCM_CALLBACK_THREAD|WAVE_FORMAT_DIRECT ...after which no sound was produced, and I killed the test, since it seemed to have frozen.
I re-ran the oss tests, and this time they seemed to run (not sure what's different). I paid closer attention to where the sound changes, and made some notes about that - see the end of the log. There's all kinds of problems - hiss, change in pitch (to several diff. results), at one point the test switched to my side speakers and turned rather loud. I'm still not sure what kind of info you are looking for (are those 0.5 sec interruptions normal?).
I am willing to re-run as many times as necessary, since I am very interested in getting hl2 to work, and sound is particularly broken.