How to create several dsp units? Help needed

Fritz Katz frtzkatz at
Fri Aug 8 15:05:28 UTC 2008

>  On Wednesday, August 6, 2008 "Alexander Motin" wrote:
> ...
>  As I understand I need somehow to create several /dev/dspX 
>  and possibly several /dev/mixerX devices to let applications 
>  operate them independently. Is it possible to do within the 
>  same pcm0 hardware device?
>  Second pcm_addchan() call creates only pcm0:play:dsp0.p1, 
>  but I need something like pcm0:play:dsp1.p0. Is in possible 
>  or dsp0 is hard bound to the pcm0?
>  If dsp0 hard bound to pcm0 then is it possible to create 
>  pcm1 dynamically within same hardware?

There is some example code in:  /usr/src/sys/dev/bktr/bktr_os.c
for the 'bktr' driver which allows a PCI TV-tuner card with the
old 'Brooktree' chipset to function in FreeBSD environs.

It creates three devices attached to the same card:

I hope this is applicable to what you are trying to do.

-- Fritz Katz


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