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Date:      Fri, 31 Mar 2000 22:01:32 +0200
From:      Martin Cracauer <cracauer@cons.org>
To:        gandalf@vilnya.demon.co.uk
Cc:        freebsd-multimedia@freebsd.org
Subject:   newpcm secondary dma buffer - why?
Message-ID:  <20000331220131.A95404@cons.org>

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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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