How do you think I discovered where to put the tone_init() in the first place? It's all good and well sticking the printks in the mixer code, but if they aren't getting out of the port...

Anyway, setting the car_rate to 115200 has changed things. I now get the behaviour that Tony wa reporting earlier - clean shutdown leads to restoration, but a yank doesn't. And now I can investigate the timings in DC mode.

Thanks.