On Mon, Nov 10, 2014 at 8:49 PM, Hans Verkuil <hverk...@xs4all.nl> wrote:
> From: Hans Verkuil <hans.verk...@cisco.com>
>
> By default dma_map_sg syncs the mapped buffer to the device. But
> buf_prepare expects a buffer syncs for the cpu and the buffer
> will be synced to the device in the prepare memop.
>
> The reverse is true for dma_unmap_sg, buf_finish and the finish
> memop.
>
> To prevent unnecessary syncs we ask dma_(un)map_sg to skip the
> sync.
>
> Signed-off-by: Hans Verkuil <hans.verk...@cisco.com>
> ---
>  drivers/media/v4l2-core/videobuf2-dma-contig.c | 29 +++++++++++++++++-----
>  drivers/media/v4l2-core/videobuf2-dma-sg.c     | 33 
> +++++++++++++++++++++-----
>  2 files changed, 50 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c 
> b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> index c4305bf..27f5926 100644
> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> @@ -317,8 +317,9 @@ static struct sg_table *vb2_dc_dmabuf_ops_map(
>                 attach->dma_dir = DMA_NONE;
>         }
>
> -       /* mapping to the client with new direction */
> -       ret = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents, dma_dir);
> +       /* Mapping to the client with new direction */
> +       ret = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
> +                        dma_dir);

Do we need this chunk?

-- 
Best regards,
Pawel Osciak
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