[linux-audio-user] Re: hardware mixing

[Mark Knecht]

On 1/22/07, Paul Davis <paul at linuxaudiosystems.com> wrote:
> On Mon, 2007-01-22 at 21:13 -0500, Lee Revell wrote:
> > On 1/22/07, ram <ram at hydrophones.com> wrote:
> > > I can confirm the RME HDSP 9632 cards and add-ons also support hardware mixing.
> > > They work really well too I may add.
> >
> > I stand corrected.  Mark was right - these devices do have hardware
> > mixing, they just implement it in an odd way, probably to keep the
> > interface similar to other OS.
>
> its not true to say that with ALSA, they support what is commonly
> understood as h/w mixing.

Is there a commonly understood meaning? I guess I'm uncommonly (or
commonly for me) in the dark about that.

> you cannot do independent open's of several
> subdevices and get the output of each subdevice mixed down to the
> outputs.

This seems a Linux Software Developer centric statement. What does it mean?

Is this a hardwired limitation of the hardware, or is it a limitation
of the current ALSA driver for the HDSP cards?

>
> yes, they do have a very powerful h/w matrix mixer, but it is not
> accessible via a series of independent subdevices. it also is not
> supported by the ALSA mixer API at this time.
>

This sounds like it's a limitation of the card so it wouldn't ever
work? Even under Windows or OSX?

What cards do support (under ALSA) a "series of independent
subdevices" which can then be output and then mixed in hardware?

Thanks,
Mark