On Fri, Jul 12, 2019 at 07:45:05PM +1000, Alexey Kardashevskiy wrote: > This is an attempt to allow DMA masks between 32..59 which are not large > enough to use either a PHB3 bypass mode or a sketchy bypass. Depending > on the max order, up to 40 is usually available.
Can you elaborate what you man with supported in detail? In the end a DMA devices DMA capability is only really interesting as a lower bound. e.g. if you have a DMA that supports 40-bit DMA addressing we could always treat it as if supports 32-bit addressing, and I thought the powerpc code does that, as the DMA API now relies on that. Did I miss something and it explicitly rejected that (in which case I didn't spot the fix in this series), or is this just an optimization to handle these devices more optimally, in which case maybe the changelog could be improved a bit.
