Subject: NeoMagic 256AV audio driver?
To: None <>
From: Jonathan Stone <jonathan@DSG.Stanford.EDU>
List: port-i386
Date: 10/19/1999 13:09:30
Thanks to everyone who gave advice on installing NetBSD on a Sony Vaio
laptop.  Works great, mostly (still some PCIbios issues and/or USB
interference with suspend/resume).

The one thing that's missing is support for the NeoMagic 256AV sound
hardware, which is used not just in Vaios but in some Dell Inspiron
laptops as well.

Doing a small Web search and asking Linux-on-Vaio users gave two
possible options to get  sound hardware working:

  a) Linux 2.2.x reportedly attaches the NeoMagic via its  SoundBlaster
     hardware-emulation; the device reportedly  attaches via
     the Linux SoundBlaster driver as an ESS1688.

  b) A native-hardware driver, using  the Neomagic hardware API
     which someone found via `psychic means'. Works on the 505 line.
     Based on Intel AC97, it has no DMA but uses a ring-buffer located
     just above the end of the 2.5Mbyte video memory.
     see for more info.

     Apparently the later Linux Xservers know about this, and leave
     empty space there, instead of using it to store fonts or other 
     data (which results in random noise instead of audio).

One tradeoff is that the SB emulation apparently gets a synthesizer;
the `native' API relies on a Windows software synthesizer

So. Do we have AC97 support? Is it OK to rewrite something based on
the Linux code (which is given as public-domain, not copyleft).
Or pursue the ESS1688 emulation?

(Does anyone have sound working on a NeoMagic 256AV already?)