On Tue, Jun 11, 2019 at 04:59:54PM +1000, Benjamin Herrenschmidt wrote: > Ah stupid me ... it's dma_set_mask that failed, since it has no idea > that the calling driver is limited to lowmem. > > That's also why the "wrong" patch worked. > > So yes, a ZONE_DMA at 30-bits will work, though it's somewhat overkill.
Well, according to Larry it doesn't actually work, which is odd.
