*BSD News Article 30822


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From: iverson@lionheart.com (Tim Iverson)
Subject: Re: BusLogi 445S and DMA Channel
Keywords: scsi buslogic bt445s
References: <2rnjgs$g1l@news-rocq.inria.fr>
Followup-To: comp.periphs.scsi
Organization: Lionheart Software
Date: Mon, 23 May 1994 23:06:25 GMT
Message-ID: <CqA2uq.84G@lionheart.com>
Lines: 42

In article <2rnjgs$g1l@news-rocq.inria.fr>,
Herve Soulard <soulard@sor.inria.fr> wrote:
>
>I've just bought a BusLogic BT445S and I've a problem with the
>DMA channel. When I load the BusLogic DOS Manager, it reports that
>no DMA channel is used. The same thing is reported by the NetBSD

This is not only normal, it is the preferred method.  The BT445s can run
either as an ISA bus-master (thus requiring a DMA channel to negotiate for
the bus) or as a VLB bus-master.  Since your BT445 is not using a DMA
channel, it is using the more desirable VLB bus-mastering and not the ISA
method.  Some earlier 445s used ISA by default to get around a potential bug
in the VLB mastering.  This has since been fixed, and now VLB is the
default.

>Does somebody know how to solve this problem ?

If you really want to run slower, you can (according to rumor) change SW2-10
from the default.

>	Orchid SuperBoard 486 DX2/66 VLB
>	20 Mbytes of RAM

This is the only really critical info ... if you switch to ISA DMA, your
BT445 will not be able to access anything beyond 16MB.

>The SCSI card works fine with DOS and with Linux 1.1.11. The
>only problem is that the DMA channel is not set.
...
>So what is wrong ?

Nothing is wrong.  Except ... well, you did cross-post this to just about
every newsgroup in creation (hrmph! how rude. ;-).  Followups have been
redirected to comp.periphs.scsi.


- Tim Iverson
  iverson@lionheart.com

--
"Deserve's got nothin' to do with it."
	- William Muney (Clint Eastwood, Unforgiven)