Subject: Re: PCMCIA sound card, yet again...
To: Jared D. McNeill <jmcneill@invisible.yi.org>
From: Jason R Thorpe <thorpej@zembu.com>
List: current-users
Date: 01/04/2001 13:39:10
On Thu, Jan 04, 2001 at 05:25:07PM -0400, Jared D. McNeill wrote:

 > 4)      DMA EMULATION
 > The Eiger Labs PC Stereo Sound Card version 2.2 provides DMA Emulation.
 > DMA Emulation supports Sound Blaster Compatibility for Windows 95 and
 > DOS sessions running under Windows 95.  Configuration for DOS only
 > requirements is still under research.  In this situation, the challenge
 > is providing DMA support through the PCMCIA socket.  PCMCIA 2.1 specifications
 > DO NOT support DMA.  Consequently, reliable execution of games and other
 > programs which have high demands on precise hardware DMA operations cannot
 > always be provided.
 > 
 > DMA Emulation for DOS/Windows 3.X is not currently available.

Right, so sounds like the driver for the card "emulates" DMA somehow,
and is really doing programmed I/O.

This is what you'll have to do.  I suggest you get the docs for the ESS 1688.
You might be able to glue it into the existing ess driver, or you might have
to start from scratch.

-- 
        -- Jason R. Thorpe <thorpej@zembu.com>