Messages in this thread | | | From | Oliver Neukum <> | Subject | Re: A question about ZONE_DMA | Date | Wed, 13 Oct 2010 16:57:07 +0200 |
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Am Mittwoch, 13. Oktober 2010, 16:52:41 schrieb Casey Dahlin: > 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?
You don't know before you load the module of the driver that needs 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?!
Parports can use DMA and are generally ISA.
Regards Oliver
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