On Tue, Apr 24, 2018 at 08:47:27AM +0100, Russell King - ARM Linux wrote: > Therefore, the default state for SWIOTLB and hence NEED_SG_DMA_LENGTH > becomes 'y' on ARM, and any defconfig file that does not mention SWIOTLB > explicitly ends up with both these enabled. Indeed, sorry. > It does look a bit weird though - patch 10 arranged stuff so that we > didn't end up with SWIOTLB always enabled, but this patch reintroduces > that with the allowance that the user can disable if so desired. I am not very happy with that patch, but I have a hard time coming up with something saner. Bascially x86_64 and mips/loongson default to SWIOTLB=y but allow to deselect it, powerpc has it optional without any real dependency and defaults to n and everyone just selects it otherwise. I suspect the right thing is to just have it always one for x86_64 and loongson and have a ppc-specific option to enable it on powerpc so that we can always use select statements. I'll do that for the next round.
