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Date:      Fri, 27 Feb 1998 13:46:55 +0100 (MET)
From:      Luigi Rizzo <luigi@labinfo.iet.unipi.it>
To:        multimedia@FreeBSD.ORG
Subject:   Vibra16X support
Message-ID:  <199802271246.NAA15760@labinfo.iet.unipi.it>

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since it looks like there are going to be more and more SB16/AWExx
cards which are really Vibra16X on the market...

the ViBRA16X should be a true full duplex card but unfortunately
has some differences from the SB16 which make my driver not work
with it (i have reports that it works in 8-bit play mode, but not
in 16-bit mode and have no reports about capture mode).

I don't have (and don't plan to buy) that card, so i cannot try
possible fixes to the driver (i don't have docs either).

If someone has this card and wants to dedicate a few minutes
to testing, here is a guess at possible changes needed (in sb_dsp.c)

1) remove/disable tests that require the secondary
   dma channel to be >=4 . the vibra16 uses two 8-bit channel
   (not such a great idea since it doubles bus traffic, plus there are
   fewer 8-bit than 16-bit channels typically available...)

2) in the code in sb_callback(), in the INIT switch,
   disable the section which swaps the two dma channels depending
   on the data format; this code is probably not necessary with
   the vibra16x (thankfully, since it considerably simplifies the
   driver)

3) in the interrupt driver, consider one of the flags as the read
   interrupt, the other one as the write interrupt.
   probably the write flag is the one labeled "8bit" in the current
   driver, the read flag is the "16bit" one.

can't be more specific at the moment, but the changes should not be so
terrible even to those without big knowledge of the driver

reports or requests for further suggestions are welcome.

	cheers
	luigi
-----------------------------+--------------------------------------
Luigi Rizzo                  |  Dip. di Ingegneria dell'Informazione
email: luigi@iet.unipi.it    |  Universita' di Pisa
tel: +39-50-568533           |  via Diotisalvi 2, 56126 PISA (Italy)
fax: +39-50-568522           |  http://www.iet.unipi.it/~luigi/
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