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Date:      Mon, 08 Mar 1999 12:07:39 -0800
From:      Jason Thorpe <thorpej@nas.nasa.gov>
To:        Andy Doran <ad@psn.ie>
Cc:        Mike Smith <mike@smith.net.au>, freebsd-hackers@FreeBSD.ORG
Subject:   Re: Erorr: isa_dmainit(2, 1024) failed 
Message-ID:  <199903082007.MAA02543@lestat.nas.nasa.gov>

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On Mon, 8 Mar 1999 18:34:38 +0000 (GMT) 
 Andy Doran <ad@psn.ie> wrote:

 > I've run into the same kind of problem when working on a driver for
 > NetBSD recently. The solution would be to use NetBSD's BUS_DMA(9), but
 > this card needs a DMA buffer which has *crazy* alignment and position
 > requirements. One of them is that the buffer needs to be within the first
 > 8MB, hence the same problem.

Well, your driver was for a non-i386 architecture :-)  And, the suggestion
I gave on port-pmax@netbsd.org is already employed by NetBSD/i386 to
"reserve" memory for ISA DMA.

That is to say, the Right solution for this is multiple memory free lists,
which NetBSD's UVM has support for.

        -- Jason R. Thorpe <thorpej@nas.nasa.gov>



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