Re: [PATCH] dma-debug: disable DMA_API_DEBUG for now

[Arnd Bergmann]

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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