Oddly behaved uaudio device

[Henry Bent <hbent%oberlin.edu@localhost>]

Hi all,

I have an Edirol UA-5 USB audio interface that works well as a basic
uaudio device.  However in this mode it is limited to 48kHz 16bit.  It
has an advanced mode that can do 96kHz 24bit and I would like to make
use of that.  Advanced mode is strange, though.  The device returns
its class as vendor (0xff) rather than audio, and its AudioStreaming
descriptor is also under vendor rather than UISUBCLASS_AUDIOSTREAM.
The ALSA folks claim that other than this, it is a well-behaved USB
audio device.  I forced uaudio to match the device and read the
AudioStreaming info from the vendor subclass, and everything looks
good but then I get a kernel panic after uaudio_round_blocksize():

audio_calcwater()
audiosetinfo()
audio_set_defaults()
audioattach()
config_attach_loc()
audio_attach_mi()
uaudio_attach()
...

Any ideas?  I feel like I'm missing a step somewhere.

-Henry