[PATCH v2 2/2] media: rockchip: rkcif: comply with minimum number of buffers requirement

[Isaac Scott]

Hi Michael,

Thank you for the patch!

Quoting Michael Riesch via B4 Relay (2026-02-20 08:15:08)
> From: Michael Riesch <michael.riesch at collabora.com>
> 
> Each stream requires CIF_REQ_BUFS_MIN=1 buffers to enable streaming.
> However, it failed with only one buffer provided.
> 
> Comply with the minimum number of buffers requirement and accept
> exactly one buffer.
> 
> Fixes: 501802e2ad51 ("media: rockchip: rkcif: add abstraction for dma blocks")
> Cc: stable at kernel.org
> Tested-by: Paul Elder <paul.elder at ideasonboard.com>
> Tested-by: Chen-Yu Tsai <wens at kernel.org>
> Signed-off-by: Michael Riesch <michael.riesch at collabora.com>
> ---
>  .../media/platform/rockchip/rkcif/rkcif-stream.c   | 44 +++++++++++-----------
>  1 file changed, 22 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/media/platform/rockchip/rkcif/rkcif-stream.c b/drivers/media/platform/rockchip/rkcif/rkcif-stream.c
> index e00010a91e8b..f15bee4f7cd7 100644
> --- a/drivers/media/platform/rockchip/rkcif/rkcif-stream.c
> +++ b/drivers/media/platform/rockchip/rkcif/rkcif-stream.c
> @@ -106,42 +106,42 @@ static int rkcif_stream_init_buffers(struct rkcif_stream *stream)
>  {
>         struct v4l2_pix_format_mplane *pix = &stream->pix;
>  
> -       stream->buffers[0] = rkcif_stream_pop_buffer(stream);
> -       if (!stream->buffers[0])
> -               goto err_buff_0;
> -
> -       stream->buffers[1] = rkcif_stream_pop_buffer(stream);
> -       if (!stream->buffers[1])
> -               goto err_buff_1;
> -
> -       if (stream->queue_buffer) {
> -               stream->queue_buffer(stream, 0);
> -               stream->queue_buffer(stream, 1);
> -       }
> -
>         stream->dummy.size = pix->num_planes * pix->plane_fmt[0].sizeimage;
>         stream->dummy.vaddr =
>                 dma_alloc_attrs(stream->rkcif->dev, stream->dummy.size,
>                                 &stream->dummy.buffer.buff_addr[0], GFP_KERNEL,
>                                 DMA_ATTR_NO_KERNEL_MAPPING);
>         if (!stream->dummy.vaddr)
> -               goto err_dummy;
> +               return -ENOMEM;
>  
>         for (unsigned int i = 1; i < pix->num_planes; i++)
>                 stream->dummy.buffer.buff_addr[i] =
>                         stream->dummy.buffer.buff_addr[i - 1] +
>                         pix->plane_fmt[i - 1].bytesperline * pix->height;
>  
> -       return 0;
> +       stream->buffers[0] = rkcif_stream_pop_buffer(stream);
> +       if (!stream->buffers[0])
> +               goto err_dummy_free;
> +
> +       stream->buffers[1] = rkcif_stream_pop_buffer(stream);
> +       if (!stream->buffers[1]) {
> +               stream->buffers[1] = &stream->dummy.buffer;
> +               stream->buffers[1]->is_dummy = true;
> +       }

Looks good to me!

Reviewed-by: Isaac Scott <isaac.scott at ideasonboard.com>

>  
> -err_dummy:
> -       rkcif_stream_return_buffer(stream->buffers[1], VB2_BUF_STATE_QUEUED);
> -       stream->buffers[1] = NULL;
> +       if (stream->queue_buffer) {
> +               stream->queue_buffer(stream, 0);
> +               stream->queue_buffer(stream, 1);
> +       }
> +
> +       return 0;
>  
> -err_buff_1:
> -       rkcif_stream_return_buffer(stream->buffers[0], VB2_BUF_STATE_QUEUED);
> -       stream->buffers[0] = NULL;
> -err_buff_0:
> +err_dummy_free:
> +       dma_free_attrs(stream->rkcif->dev, stream->dummy.size,
> +                      stream->dummy.vaddr,
> +                      stream->dummy.buffer.buff_addr[0],
> +                      DMA_ATTR_NO_KERNEL_MAPPING);
> +       stream->dummy.vaddr = NULL;
>         return -EINVAL;
>  }
>  
> 
> -- 
> 2.39.5
> 
> 
>