(In reply to comment #3)
> Created attachment 86598 [details] [review] [review]
> use hw generated cts and n values rather than the sw programmed values
> 
> Does this patch help?  If not, it may be worth adding some slop to the
> r600_hdmi_predefined_acr[] table to handle rounding differences so the
> appropriate defined values get selected.

A quick test indicates that this patch does indeed solve the issue. I've played
three minutes of AC3 audio without any interruptions.