On Thu, Feb 09, 2023 at 09:33:06AM +0000, JiaJie Ho wrote: . > The DMA can only support 32-bit addressing. Isn't the DMA mapping API supposed to solve this automatically for you? IOW just do the dma_map call and it should transparently copy any high addresses to lowmem bounce buffers. Cheers, -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt