Date: Fri, 31 Mar 2000 19:24:18 -0500 From: "Charles Anderson" <caa@columbus.rr.com> To: Martin Cracauer <cracauer@cons.org> Cc: gandalf@vilnya.demon.co.uk, freebsd-multimedia@FreeBSD.ORG Subject: Re: newpcm secondary dma buffer - why? Message-ID: <20000331192418.B13072@midgard.dhs.org> In-Reply-To: <20000331220131.A95404@cons.org>; from cracauer@cons.org on Fri, Mar 31, 2000 at 10:01:32PM %2B0200 References: <20000331220131.A95404@cons.org>
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I'd like to know why too, it went in mid December, and before that mmap
actually worked. I know I had drivers from 12/19/1999 that did mmap'ed
sound out to /dev/dsp.
-Charlie
On Fri, Mar 31, 2000 at 10:01:32PM +0200, Martin Cracauer wrote:
> Cameron, multimedia folks,
>
> could you explain why the newpcm driver uses a secondary buffer to
> collect data before it transmits it to the soundcard?
>
> struct _pcm_channel {
> [...]
> snd_dbuf buffer2nd;
> };
>
> Please don't say "it does buffering", I assume that :-) But so far
> I've been under the impression that such things are unneeded in
> today's soundcards and that it is extremly hard to get the mmap API to
> work with such a construction in between.
>
> Thanks
> Martin
> --
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> Martin Cracauer <cracauer@cons.org> http://www.cons.org/cracauer/
> BSD User Group Hamburg, Germany http://www.bsdhh.org/
>
>
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--
Charles Anderson caa@columbus.rr.com
No quote, no nothin'
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