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From: mlelstv@serpens.rhein.de (Michael van Elst)
Newsgroups: comp.unix.bsd.netbsd.misc
Subject: Re: sd0: DMA beyond ISA whazzat?
Date: 24 Nov 1995 11:53:42 +0100
Organization: dis-
Lines: 27
Message-ID: <49487m$cqq@serpens.rhein.de>
References: <48snme$1p1g@info4.rus.uni-stuttgart.de> <48uqpa$j5j@serpens.rhein.de> <MICHAELV.95Nov22211945@MindBender.HeadCandy.com>
NNTP-Posting-Host: serpens.rhein.de
michaelv@MindBender.HeadCandy.com (Michael L. VanLoon) writes:
>In article <48uqpa$j5j@serpens.rhein.de> mlelstv@serpens.rhein.de (Michael van Elst) writes:
> schweikh@zeiss.ito.uni-stuttgart.de (Jens Schweikhardt) writes:
> >recently while compiling a new kernel (i386) I got the following
> >messages:
> > sd0: DMA beyond ISA
> NetBSD 1.0 does not implement bounce buffers to fix hardware limits.
> NetBSD 1.1 does implement bounce buffers for some (all ?) drivers
> that need them.
>This is incorrect. It only does this for devices that use the
>motherboard DMA chips. DMA initiated on the far side of the ISA bus
>(i. e. on a peripheral) is impossible above 16MB. NetBSD does not yet
>have bounce-buffer support for this.
You are right. Sorry for any confusion I might have produced.
Regards,
--
Michael van Elst
Internet: mlelstv@serpens.rhein.de
"A potential Snark may lurk in every tree."