Messages in this thread | | | From | Tomasz Figa <> | Date | Mon, 26 Jul 2021 13:04:53 +0900 | Subject | Re: [PATCHv3 8/8] videobuf2: handle non-contiguous DMA allocations |
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On Mon, Jul 26, 2021 at 12:59 PM Sergey Senozhatsky <senozhatsky@chromium.org> wrote: > > On (21/07/22 19:26), Dafna Hirschfeld wrote: > > Also, the 'cookie' cb returns buf->dma_addr which is not initialized for > > the noncontiguous api. So it is not clear how drivers should use the new api. > > Many drivers call vb2_dma_contig_plane_dma_addr which returns the cookie. > > Hmm, that's a good find. Is ->dma_addr the same as what we have in > sgt.sgl->dma_address for non-contig?
Yes. As per [1]:
"The return sg_table is guaranteed to have 1 single DMA mapped segment as indicated by sgt->nents, but it might have multiple CPU side segments as indicated by sgt->orig_nents."
[1] https://www.kernel.org/doc/html/latest/core-api/dma-api.html#part-ii-non-coherent-dma-allocations
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