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Subject: Re: linux-next: build failure after merge of the final tree
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From: David Miller <davem@davemloft.net>
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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: Sat, 22 Sep 2012 07:46:40 +1000

> Right, but on ppc, GFP_DMA is a nop (no separate ZONE_DMA, or rather all
> of memory is ZONE_DMA). It's always been like that afaik.
> 
> We could support ISA device limited addressability using the iommu but
> that would involve a map/unmap type API (which I remember we did support
> in the old days by passing NULL to pci_map_*, but we dropped that along
> the way).

I think I'm going to just end up restricting this driver to X86
as was originally suggested.

There seems to be no real consistent Kconfig protection for users
of isa_virt_to_bus() and friends.

We know that ISA_DMA_API doesn't do it, and ISA doesn't do it either
as powerpc also allows that to bet set for CHRP and friends.

Thanks.