Is it possible to communicate with the folks that designed the Xmega? Has Trondheim been obliterated? Is it now only a blank spot on Google maps, like area 51?
The USB silicon seems to do something desirable about disabling DFLL when we are suspended and not receiving SOF. That works well. It also tries to enable DFLL when we are resumed and again receiving SOF. Sometimes this works and sometimes doesn't, with disastrous results to our clock frequency. None of this appears in the manual, as far as I can see. I might be able to kludge Atmel's boo boo, but it would be nice to communicate to someone with more knowledge of the silicon.