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Date:      Wed, 12 Feb 1997 10:19:44 -0700 (MST)
From:      Terry Lambert <terry@lambert.org>
To:        bde@zeta.org.au (Bruce Evans)
Cc:        julian@whistle.com, terry@lambert.org, freebsd-hackers@freebsd.org, Shimon@i-Connect.Net
Subject:   Re: Raw I/O Question
Message-ID:  <199702121719.KAA00730@phaeton.artisoft.com>
In-Reply-To: <199702120822.TAA06992@godzilla.zeta.org.au> from "Bruce Evans" at Feb 12, 97 07:22:17 pm

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> >it then calls the strategy routine for the device
> >which gets the kv region, 
> >and extracts the phyical addresses again and 
> >sets up the DMA
> >and then waits
> >
> >DMA is directly into the users pages..
> 
> Only for devices and device drivers that support and use DMA.

And are not limited to 24 bit ISA I/O when the physical memory
target of the DMA is not above 16M.  These will be bounced and
then copied to the users pages.


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.



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