[LAD] Firewire bus analysis - Digidesign 003 Rack

Hi folks, I have done some firewire bus analysis on the 003 Rack and posted last year some of my findings on ffado.org wiki. inter Today I got back into it and managed to modify Clemens' snd-dice driver to activate the 003R and made a standalone driver to play out of 2 channels! It's a non standard protocol, because you have to send particular requests and wait for particular responses but I have documented as much as I can. Unfortunately during playback there are 2 outstanding issues: 1) There is extraneous low level noise when sound is routed through channel 1 or channel 18 (first and last pcm channel). When sound is routed into channel 1, noise is heard in channel 2 and channel 1 sounds normal. When sound is routed into channel 18, similar noise is heard in channel 1 but nothing else is heard. 2) I don't know why but the device spits out a request on the bus about 10 times per second which interrupts playback for very short intervals causing choppy playback. I had a similar problem when trying to make the 003R work under ffado. I have examined the behaviour of the device under windows and it does not generate these packets. Could it be the way the iso resources are being handled? I am allocating a tx and rx stream separately since without both, the device stops transmitting in under 2 seconds, while with this driver, it stays stable indefinitely. I could use some advice on where to look next. Damien