This looks like a workaround for a userspace bug that would affect all USB audio devices. What period/buffer sizes are xawtv/tvtime trying to use?
I have similar concerns, although I don't know what the right solution is. For example, the last time Mauro tweaked the latency in tvtime, it broke support for all cx231xx devices (note that tvtime and xawtv share essentially the same ALSA code):
http://git.linuxtv.org/cgit.cgi/tvtime.git/commit/?id=3d58ba563bfcc350c180b5...
It seems like there is definitely something wrong with the latency/period selection in both applications, but we need some insight from people who are better familiar with the ALSA subsystem for advice on the "right" way to do low latency audio capture (i.e. properly negotiating minimal latency in a way that works with all devices).
Devin