From owner-freebsd-hackers  Thu Jul  6 23:18:21 2000
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Date: Thu, 6 Jul 2000 23:18:05 -0700 (PDT)
From: Matthew Jacob <mjacob@feral.com>
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To: Kelly Yancey <kbyanc@posi.net>
Cc: "Kenneth D. Merry" <ken@kdm.org>,
	Zhihui Zhang <zzhang@cs.binghamton.edu>, freebsd-hackers@FreeBSD.ORG
Subject: Re: Max DMA size
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>   Hmm. My knowledge may be a bit dated in this matter, but as I recall the
> 8237 DMA controller standard on PCs only supports DMA requests up to 128k (and
> then only on the upper 4 DMA channels). The low 4 DMA channels were
> byte-granular and could only transfer 64k. Am I correct in assuming from this
> discussion that the state of affairs is somewhat different nowadays?

Uh, yeah. Standard PCI h/w usually has 32 bit dma engines, and a lot have 64
bit.




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