Re: [Alsa-user] AD1985 full-duplex(?)

[Florian S. <mis...@gm...>]

On Wed, 18 Aug 2004 08:27:10 -0700
Shaya Potter <sp...@cs...> wrote:

> A question I've asked, but haven't gotten an answer is why do we have
> to resort to dmix (i.e. something handled in userspace, and hence
> subject to the scheduler's whims as only one process can have control
> over the device) instead of being handled by the kernel driver itself
> (and hence not subject to the scheduler's whims as much)

I know how much the ALSA developers favor the modular approach having sw
mixing done in userspace. I think this is suboptimal for several
reasons:

1] the scheduling problems you mentioned

2] legacy OSS apps need to be run via aoss which still stinks for many
apps

3] the user has to edit configuration files, which is a showstopper for
newbies and people who have never had to follow a rigorous syntax.

I would suggest writing another "dummy" soundcard module which would
sit "ontop" of the normal alsa driver and which does nothing but provide
sw mixing access [including the needed resampling and mixing]. 

This module could then be used by the OSS emu and provide sw mixing for
legacy OSS apps as well.

Also, while duplicating some code from alsalib, it would still keep the
sw mixing/resampling stuff out of the real driver..

flo

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