the main benefit this gives for now is that via686 audio devices on
motherboards with ac97 codecs that do not support vra will be able to use
sample rates other than 48khz.
this gives us several benefits, including:
* easier extensibility- new optional methods can be added to
ac97/mixer/channel classes without having to fixup every driver.
* forward compatibility for drivers, provided no new mandatory methods are
added.
once built, 'kld_load snd_driver; kldunload snd_driver' will load all sound
drivers and unload all unattached ones. attached drivers do not yet support
unloading.
