From alsa-devel-owner@alsa.jcu.cz  Mon Oct  5 11:28:26 1998
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Date: Mon, 5 Oct 1998 02:26:31 -0700 (PDT)
From: Brion Vibber <brion@pobox.com>
To: Jaroslav Kysela <perex@jcu.cz>
cc: alsa-devel@jcu.cz
Subject: Re: Multiple sound cards
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On Mon, 5 Oct 1998, Jaroslav Kysela wrote:

> On Sun, 4 Oct 1998, Brion Vibber wrote:
> 
> > BUT I'm having problems with OSS. :( The script to make the sound devices
> > in the alsa-driver package clobbered the device numbers some of the dsp
> > devices, so I had to fix dsp1 from 14,5 to 14,19. Also dsp8 was wrong but
> > there doesn't seem to be anything on the corrected device, and dsp16
> > shouldn't exist as far as I can tell.
> 
> /dev/dsp8 means 8-bit unsigned format and /dev/dsp16 means 16-bit signed
> little endian format.. These names doesn't have anything with card number.

Just curious, where did this naming scheme came from? It's not consistent
with what the OSS drivers I've used seem to have so I'm a little confused
about it... (I mean, this is supposed to be compatible with OSS, so why
act quite differently from it?)

Under OSS/Linux on my machine /dev/dsp0 and /dev/dsp1 respectively were
the first and second PCM devices on the AudioPCI, and several after that
(2 to 10 I think) went to SoftOSS virtual devices which I briefly fiddled
with but gave up on since OSS apps don't cooperate enough to actually make
it useful for anything.

> pcm01 -> /dev/adsp (alternate DSP),

Hmm, maybe I'll just change my dsp1 to match adsp to keep things looking
consistent on my end. Again, any reason for this apparent inconsistency
with OSS?

> PCM devices 2-3 aren't mapped to OSS
> space... This is due to another scheme (ALSA have soundcard and PCM
> devices; OSS have only devices).

Umm, okay. Don't suppose it's that big a deal since most people don't have
multiple soundcards anyway, but is there a real technical reason for this?
The only one I can think of is that it'd be a pain to think up a
consistent and convenient mapping to linearly-named OSS devices from
two-dimensionally named ALSA devices, but you're not keeping with that
convention anyway so that can't be it.

Maybe I'm just slow on the uptake right now, I really should get some
sleep as I have class in 6 hours and only slept 4 hours yesterday
morning, but this strikes me as either not thought through quite as much
as it should have or a deliberate attempt to make application programmers
port their apps to the native ALSA interface by making compatibility a
little limited... ;)

-- brion vibber (brion@pobox.com)



