> If trying to avoid big changes and only fixing particular problem with > particular device not working on arm64, I think best way is to > alter__swiotlb_dma_supported() in arch/arm64/mm/dma-mapping.c to detect > and decline (with -EIO) mask that is unsupported by device connection. > This will cover both dma_mask and coherent_dma_mask. > > This has to be combined with some way to explicitly extract information > about limitations. Checking device parent's dma masks won't work unless > somebody bothers to populate them.
I'm trying to bring together a patch doing this, will post that when ready
