Re: [PATCH 2/3] dma: override "dma_flags_set_dmaflush" for sn-ia64

Jes Sorensen
2007-08-22T07:46:24Z

Matthew Wilcox wrote:
> So, let me try to understand ... your hardware allows writes from the
> device to pass other writes from the device? Doesn't that violate the
> PCI spec? I'm thinking about this (page 43 of PCI 2.3):

Hi Matthew,

Yes I believe this behavior on sn2 is 'bending' the PCI spec a bit. The
problem is that the NUMA fabric is a routed network in itself so there
can be multiple paths between the device and the physical memory it DMAs
to/from.

Cheers,
Jes