Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH] dma-debug: disable DMA_API_DEBUG for now | Date | Fri, 5 Jun 2009 15:57:56 +0100 |
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On Friday 05 June 2009, FUJITA Tomonori wrote: > I think that the better fix can handle both cases per device: > > - multiple identical dma addresses should not happen (with devices > behind hardware IOMMU) > - multiple identical dma addresses could happen
I guess you could also have the case where for a given range of addresses, you use a linear mapping and the dma addresses can be identical, while for other physical addresses you would rely on address translation.
For example on PowerPC/Cell with infiniband adapters, you can get linear mapping behavior for DMA_ATTR_WEAK_ORDERING but IOMMU translation without that flag, for the same device and same physical address.
Arnd <><
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