Re: Problem with AMD chipsets. Was "Re: problems doing direct dmafrom a pci device to pci-e device"

From: Clemens Ladisch
Date: Fri Sep 30 2011 - 04:46:12 EST


Mark Hounschell wrote:
> We have no problem with this same configuration using a MB with an
> nvidia chipset. I suspect it might have something to do with the the MB
> that usines the AMD chipset having an IOMMU, but I really don't know for
> sure. I've also read something in the AMD chipset docs about some type
> of restrictions on peer to peer transfers but again I really have no
> idea if this is related to why I'm having this problem.

According to the published RS780 docs, "P2P traffic could be only memory
writes" (RPR 2.7). In any case, check the P2P bits (MISC is described
in BDG 2.4).


Regards,
Clemens
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