Messages in this thread | | | Date | Tue, 11 Nov 2008 14:32:46 -0600 (CST) | From | Christoph Lameter <> | Subject | Re: [Q] Why does dma_alloc_coherent() of ia64 GFP_DMA? |
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On Tue, 11 Nov 2008, FUJITA Tomonori wrote:
> Is it because it does some kinda address translation > (provider->dma_map_consistent) later? The zone flag is meaningless if > you do sorta address translation (e.g. hardware IOMMU like VT-d).
Yes it can do address translation. Therefore a < 4G address can show up at any 64 bit address. So no need for a special DMA zone. The same is true for more x86_64 platforms that have an IOMMU.
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