Date: Fri, 20 Jan 2006 11:20:12 +0100
Message-ID: <s5hd5in9p5v.wl%tiwai@suse.de>
From: Takashi Iwai <tiwai@suse.de>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Lee Revell <rlrevell@joe-job.com>, Adrian Bunk <bunk@stusta.de>,
       linux-kernel@vger.kernel.org, alsa-devel@alsa-project.org,
       perex@suse.cz
Subject: Re: [Alsa-devel] Re: RFC: OSS driver removal, a slightly	different	approach
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At Thu, 19 Jan 2006 22:09:33 +0000,
Alan Cox wrote:
> 
> On Iau, 2006-01-19 at 14:01 -0500, Lee Revell wrote:
> > > > Hmm.  From sound/oss/kahlua.c:
> > > > 
> > > > /*
> > > >  *      Initialisation code for Cyrix/NatSemi VSA1 softaudio
> > > >  *
> > > >  *      (C) Copyright 2003 Red Hat Inc <alan@redhat.com>
> > > >  *
> > > > 
> > > > Why was a new OSS driver written and accepted at such a late date, when
> > > > OSS was already deprecated?
> > > 
> > > You'll find out that it must be pretty easy to write kahlua driver for
> > > ALSA, too, if you look at kahlua.c.  Just need a hardware to certify
> > > if this is really demanded...
> > 
> > Yes, it looks simple enough to write a driver without the hardware, as
> > long as someone volunteers to test it...
> 
> Most of the Kahlua logic is in the SB driver. It was a wrapper added
> later to make autoconfiguration simple for end users. CS55x0 (VSA1
> variants) are generic sound blaster 16 emulation via SMI traps. There
> are certain things you must not do
> 
> 1.	Use a 64K or 128K in 16bit ring buffer
> 2.	Disable/Enable DMA on the sound channel while audio is running
> 
> #1 causes the box to hang dead (firmware emulation bug)
> #2 mistakenly flushes the FIFOs so breaks up the audio
> 
> Otherwise its SB16 compatible.

Thanks for good hints.

BTW, I remember that there was a driver for native geode audio support
at the time of ALSA 0.5.x or earlier.  I must have the code somewhere
in my storage.  The porting would be much much harder than kaulha (sb 
emulation), though.


Takashi
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