Re: [PATCH v7 15/28] media: rockchip: rga: align stride to 4 bytes

[Michael Tretter <m.tretter@pengutronix.de>]

On Thu, 21 May 2026 00:44:20 +0200, Sven Püschel wrote:
> Add an alignment setting to rga_hw to set the desired stride alignment.
> As the RGA2 register for the stride counts in word units, the code
> already divides the bytesperline value by 4 when writing it into the
> register. Therefore fix the alignment to a multiple of 4 to avoid
> potential off by one errors due from the division.
> 
> Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
> Signed-off-by: Sven Püschel <s.pueschel@pengutronix.de>

Reviewed-by: Michael Tretter <m.tretter@pengutronix.de>

> 
> ---
> Changed in v6:
> - Drop unintended change from fmt->fourcc to pix_fmt->pixelformat
>   Flagged by Sashiko:
>   https://sashiko.dev/#/patchset/20260428-spu-rga3-v5-0-eb7f5d019d86%40pengutronix.de?part=15
> ---
>  drivers/media/platform/rockchip/rga/rga-hw.c |  1 +
>  drivers/media/platform/rockchip/rga/rga.c    | 11 ++++++-----
>  drivers/media/platform/rockchip/rga/rga.h    |  1 +
>  3 files changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/media/platform/rockchip/rga/rga-hw.c b/drivers/media/platform/rockchip/rga/rga-hw.c
> index 9881c14f908d5..dac3cb6aa17d3 100644
> --- a/drivers/media/platform/rockchip/rga/rga-hw.c
> +++ b/drivers/media/platform/rockchip/rga/rga-hw.c
> @@ -580,6 +580,7 @@ const struct rga_hw rga2_hw = {
>  	.max_width = MAX_WIDTH,
>  	.min_height = MIN_HEIGHT,
>  	.max_height = MAX_HEIGHT,
> +	.stride_alignment = 4,
>  
>  	.start = rga_hw_start,
>  	.handle_irq = rga_handle_irq,
> diff --git a/drivers/media/platform/rockchip/rga/rga.c b/drivers/media/platform/rockchip/rga/rga.c
> index bf6bbcbfc869b..d080cb672740b 100644
> --- a/drivers/media/platform/rockchip/rga/rga.c
> +++ b/drivers/media/platform/rockchip/rga/rga.c
> @@ -234,10 +234,10 @@ static int rga_open(struct file *file)
>  	ctx->in = def_frame;
>  	ctx->out = def_frame;
>  
> -	v4l2_fill_pixfmt_mp(&ctx->in.pix,
> -			    ctx->in.fmt->fourcc, def_width, def_height);
> -	v4l2_fill_pixfmt_mp(&ctx->out.pix,
> -			    ctx->out.fmt->fourcc, def_width, def_height);
> +	v4l2_fill_pixfmt_mp_aligned(&ctx->in.pix, ctx->in.fmt->fourcc,
> +				    def_width, def_height, rga->hw->stride_alignment);
> +	v4l2_fill_pixfmt_mp_aligned(&ctx->out.pix, ctx->out.fmt->fourcc,
> +				    def_width, def_height, rga->hw->stride_alignment);
>  
>  	if (mutex_lock_interruptible(&rga->mutex)) {
>  		ret = -ERESTARTSYS;
> @@ -393,7 +393,8 @@ static int vidioc_try_fmt(struct file *file, void *priv, struct v4l2_format *f)
>  		fmt = &hw->formats[0];
>  
>  	v4l2_apply_frmsize_constraints(&pix_fmt->width, &pix_fmt->height, &frmsize);
> -	v4l2_fill_pixfmt_mp(pix_fmt, fmt->fourcc, pix_fmt->width, pix_fmt->height);
> +	v4l2_fill_pixfmt_mp_aligned(pix_fmt, fmt->fourcc,
> +				    pix_fmt->width, pix_fmt->height, hw->stride_alignment);
>  	pix_fmt->field = V4L2_FIELD_NONE;
>  
>  	return 0;
> diff --git a/drivers/media/platform/rockchip/rga/rga.h b/drivers/media/platform/rockchip/rga/rga.h
> index 04aeb7b429523..38518146910a6 100644
> --- a/drivers/media/platform/rockchip/rga/rga.h
> +++ b/drivers/media/platform/rockchip/rga/rga.h
> @@ -150,6 +150,7 @@ struct rga_hw {
>  	size_t cmdbuf_size;
>  	u32 min_width, min_height;
>  	u32 max_width, max_height;
> +	u8 stride_alignment;
>  
>  	void (*start)(struct rockchip_rga *rga,
>  		      struct rga_vb_buffer *src, struct rga_vb_buffer *dst);
> 
> -- 
> 2.54.0
> 
> 

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