On Tue, Mar 13, 2018 at 01:39:44PM +0000, Chris Obbard wrote:
> >> +- loopback:  if this property is present then the dai is configured in
> >> +             loopback mode where the output fifo is redirected to the input
> >> +             fifo.

> > This really doesn't seem like something that ought to go into the DT
> > and hence ABI given that there's obviously no reason to use this in
> > production.  Just make it be a #define in the code or something.

> It would be nice to have this as an optional devicetree property so
> when testing JACK latency etc I don't have to manually re-compile a
> kernel...

You'll have to rebuild your DT anyway, I'm not sure the kernel is that
much of a difference...  For your use case you'd want a regular runtime
ALSA control, not a DT property anyway.  That would be fine.