[Xen-devel] Re: mthca use of dma_sync_single is bogus

[Lukas Hejtmanek <xhejtman@xxxxxxxxxxx>]

On Mon, Jul 09, 2007 at 11:48:06PM -0700, Roland Dreier wrote:
> Yes, for example on ppc 4xx the amount of coherent memory is quite
> small by default (address space for non-cached mappings is actually
> what is limited, but it amounts to the same thing).
> 
> Maybe the least bad solution is to change to using dma_map_single()
> instead of pci_map_sg() in mthca_memfree.c.

And what about the attached patch to mthca_memfree? It changes alloc_pages for
pci_alloc_consistent. Using it, I can enable FMR and the driver runs fine.

Indeed, it does not solve problem with dma_sync_single() per se, on the other
hand, with pci_alloc_consistent() swiotlb is not needed thus dma_sync_single()
does nothing. But I agree it is not conceptual.

-- 
Lukáš Hejtmánek

patch
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