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From: Casey Dahlin <cdahlin@redhat.com>
To: linux-kernel@vger.kernel.org
Subject: A question about ZONE_DMA
Date: Wed, 13 Oct 2010 10:52:41 -0400	[thread overview]
Message-ID: <20101013145240.GE12467@foucault.redhat.com> (raw)

Hi all,

So if I understand correctly, ZONE_DMA exists to separate and preserve the
chunk of memory to which older ISA cards are capable of doing DMA. The question
that arises for me is:

1) Why do /all/ 32-bit boxes have a ZONE_DMA when surely only a tiny and
shrinking number of them have a need for it?

2) Why do /any/ 64-bit boxes have a ZONE_DMA? Is there really some godless
monster out there who put an early ISA bridge and a 64-bit CPU on the same
motherboard?!

Can someone shed light on what I'm missing?

--CJD

             reply	other threads:[~2010-10-13 14:52 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-13 14:52 Casey Dahlin [this message]
2010-10-13 14:57 ` A question about ZONE_DMA Oliver Neukum
2010-10-13 14:57 ` Arnd Bergmann
2010-10-13 15:12 ` Casey Dahlin
2010-10-13 16:07   ` Andi Kleen
2010-10-13 20:53 ` David Rientjes

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