[linux-audio-dev] dmix and jack

[Lee Revell]

On Mon, 2006-01-30 at 15:14 -0500, Paul Davis wrote:
> On Mon, 2006-01-30 at 20:05 +0000, James Courtier-Dutton wrote:
> > voidcreature at paradise.net.nz wrote:
> > > Has anyone managed to successfully get jackd talking to dmix?
> > > 
> > > My dmix setup works fix (i run VoIP stuff, artsd, and other assorted junk 
> > > through it daily).
> > > 
> > > jackd works great when connect to hw:0,0 or to plughw:0,0 (with the warning), 
> > > but if I point it at my dmix'd "default"  it sits there with 100% CPU usage, 
> > > and doesn't otherwise operate.
> > > 
> > > Does anyone have this combination of jack and dmix working?
> > > 
> > 
> > It is due to the fact that the alsa programming in jackd has been 
> > implemented wrongly. The poll revents are not handled correctly.
> > This results is OK operation when using hw:0,0, but likely to fail for 
> > more exotic alsa configurations like dmix.
> 
> i will happily take a patch for this. or is it just the MMAP_COMPLEX
> patch and nothing more?

No, this is a separate issue (ALSA still must be patched to work with
JACK + MMAP_COMPLEX).  The ALSA developers won't take the patch, they
say it's actually JACK that's wrong, but I haven't seen a patch, nor do
I know exactly what the problem is.

Lee