Any advice?
Stick with what works.
The driver will accept any sample rate and ask the RT2232 for it ...
but since there is no real documentation, there is no way to know if
that will really work or create issue inside the RTL2232 chip ...
That's the problem with using stuff in ways they weren't design for.
For consistent results, you should stick with commonly used samples
rates like 1M 1.024M 1.2M 2M 2.048M 2.4M Avoid things lower than 1M
and avoid weird, not-often used, values.
Cheers,
Sylvain