Re: alpha iommu fixes

[Richard Henderson]

On Tue, May 22, 2001 at 01:48:23PM -0700, Jonathan Lundell wrote:
> 64KB for 8-bit DMA; 128KB for 16-bit DMA. [...]  This doesn't
> apply to bus-master DMA, just the legacy (8237) stuff.

Would this 8237 be something on the ISA card, or something on
the old pc mainboards?  I'm wondering if we can safely ignore
this issue altogether here...

> There was also a 24-bit address limitation.

Yes, that's in the number of address lines going to the isa card.
We work around that one by having an iommu arena from 8M to 16M
and forcing all ISA traffic to go through there.


r~
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