Re: [PATCH]: PCI: GART iommu alignment fixes [v2]

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But I think Prarit is right with this change. If the interface defines
this behavior the IOMMU drivers have to implement it. I am just
wondering that the problem never showed up before. The GART driver is a
few years old now.


Joerg -- there's an easy explanation for this. This will only happen when a 32-bit device requests DMA memory and all memory below 4G is used. Just doing a quick overview of a few systems, allocated DMA memory is usually less than 512M of the system memory so it is unlikely a system hits the 4G limit.

In addition to that most systems do not reserve all or most of the lower 4G in the e820 maps. Those that do are usually larger systems.

ie) The only reason we're seeing this now is because large memory footprint systems are coming online -- IMO ;)

P.

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