Comment 83 for bug 1136110

It seems that Alan's asynchronous DAC is not the only one that worked fine. My friend has an Arce MDAC2 which however is labeled "asynchronous", not affected by this bug. That DAC supports only two sample rates: 44100Hz and 48000Hz at 16bit. I happen to know it use a BB PCM1792 as its DAC chip, but not sure about the USB controller chip. It might be BB PCM2707. Arce MDAC2 has a BB SRC4392 that asynchronously upsamples input audio to 192Khz to reduce jitter, which is the reason it's labeled "asynchronous".

I searched google and find this article: http://www.pstracks.com/pauls-posts/myth-asynchronous-dac/6291/
"Now, many DACS have asynchronous USB inputs, but that doesn’t mean they are an asynchronous DAC. To qualify as an asynchronous DAC, every input of the DAC (not just the USB) would be asynchronous – where the designer would throw away the source clock and rely only on the DAC’S internal clock. There are scarce few of these around."

According to this article, since Arce MDAC2 is still using the source clock, it can not qualify as a "real" asynchronous DAC.

As for the CONFIG_USB_DEBUG enabled kernel, I haven't built a linux kernel before, but I'll try to figure it out later.