Re: [Patch 2/2] media: ti-vpe: vpe: allow use of user specified stride

From: Tomi Valkeinen
Date: Wed Feb 15 2017 - 06:23:23 EST


Hi,

On 13/02/17 15:06, Benoit Parrot wrote:
> Bytesperline/stride was always overwritten by VPE to the most
> adequate value based on needed alignment.
>
> However in order to make use of arbitrary size DMA buffer it
> is better to use the user space provide stride instead.
>
> The driver will still calculate an appropriate stride but will
> use the provided one when it is larger than the calculated one.
>
> Signed-off-by: Benoit Parrot <bparrot@xxxxxx>
> ---
> drivers/media/platform/ti-vpe/vpe.c | 28 ++++++++++++++++++++--------
> 1 file changed, 20 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/media/platform/ti-vpe/vpe.c b/drivers/media/platform/ti-vpe/vpe.c
> index 2dd67232b3bc..c47151495b6f 100644
> --- a/drivers/media/platform/ti-vpe/vpe.c
> +++ b/drivers/media/platform/ti-vpe/vpe.c
> @@ -1597,6 +1597,7 @@ static int __vpe_try_fmt(struct vpe_ctx *ctx, struct v4l2_format *f,
> struct v4l2_plane_pix_format *plane_fmt;
> unsigned int w_align;
> int i, depth, depth_bytes, height;
> + unsigned int stride = 0;
>
> if (!fmt || !(fmt->types & type)) {
> vpe_err(ctx->dev, "Fourcc format (0x%08x) invalid.\n",
> @@ -1683,16 +1684,27 @@ static int __vpe_try_fmt(struct vpe_ctx *ctx, struct v4l2_format *f,
> plane_fmt = &pix->plane_fmt[i];
> depth = fmt->vpdma_fmt[i]->depth;
>
> - if (i == VPE_LUMA)
> - plane_fmt->bytesperline = (pix->width * depth) >> 3;
> - else
> - plane_fmt->bytesperline = pix->width;
> + stride = (pix->width * fmt->vpdma_fmt[VPE_LUMA]->depth) >> 3;
> + if (stride > plane_fmt->bytesperline)
> + plane_fmt->bytesperline = stride;

The old code calculates different bytes per line for luma and chroma,
but the new one calculates only for luma. Is that correct?

Tomi

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