From alsa-devel-owner@alsa.jcu.cz  Mon Nov 16 17:10:22 1998
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To: alsa-devel@jcu.cz
cc: Jaroslav Kysela <perex@jcu.cz>, sailer@ife.ee.ethz.c
Subject: Re: vid4linux/bttv sound support? 
In-reply-to: Your message of "Mon, 16 Nov 1998 13:30:20 +0100."
             <36501ADC.A9CB0595@ife.ee.ethz.ch> 
Date: Mon, 16 Nov 1998 10:10:35 -0500
From: Paul Barton-Davis <pbd@op.net>
Reply-To: alsa-devel@alsa.jcu.cz
Sender: alsa-devel-owner@alsa.jcu.cz
Precedence: list

In message <36501ADC.A9CB0595@ife.ee.ethz.ch>you write:
>Jaroslav Kysela wrote:
>
>> It isn't very true. Maybe better term is OSS soundcore which allows hooks
>> for devices which uses OSS API, thus this isn't very useable for native
>> devices for ALSA driver.
>
>Why not? soundcore isn't dependent on OSS, it just multiplexes minors.
>If you miss something, add it to soundcore.

The comments at the top of sound_core.c say:

 *	Top level handler for the sound subsystem. Various devices can
 *	plug into this. The fact they dont all go via OSS doesn't mean 
 *	they don't have to implement the OSS API. There is a lot of logic
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 *	to keeping much of the OSS weight out of the code in a compatibility
 *	module, but its up to the driver to rember to load it...


Further, the list of minor number mappings says:

 *      0	*16		Mixers
 *	1	*8		Sequencers
 *	2	*16		Midi
 *	3	*16		DSP
 *	4	*16		SunDSP
 *	5	*16		DSP16
 *	6	--		sndstat (obsolete)
 *	7	*16		unused
 *	8	--		alternate sequencer (see above)
 *	9	*16		raw synthesizer access

and although it doesn't say it, "sequencers", "mixers", "DSP"
etc. mean "OSS-like". If we hook up the ALSA sequencer to (14,1), for
example, and playmidi opens it, its going to get quite a suprise (I
hope, since I don't really want the ALSA sequencer to replicate the
OSS interface). Likewise for other programs that "expect"
/dev/whatever to present an OSS-like interface. So, sure, sound_core
doesn't impose this, but its part of a set of assumptions that do.

--p





