On Wed, Aug 19, 2020 at 02:49:01PM +0200, Tomasz Figa wrote: > With the default config it doesn't, but with > CONFIG_DMA_NONCOHERENT_CACHE_SYNC enabled it makes dma_pgprot() keep > the pgprot value as is, without enforcing coherence attributes. Which isn't selected on arm64, and that is for a good reason. > AFAIK dma_cache_sync() isn't the only way to perform the cache > synchronization. Yes, it is the only documented way to do it. And if you read the whole series instead of screaming you'd see that it provides a proper way to deal with non-coherent memory which will also work with arm64. instead of screaming > By the way, as a videobuf2 reviewer, I'd appreciate being CC'd on any > series related to the subsystem-facing DMA API changes, since > videobuf2 is one of the biggest users of it. The cc list is too long - I cc lists and key maintainers. As a reviewer should should watch your subsystems lists closely.