linux-kernel - Re: [PATCH] media: renesas: vin: Fix RAW8 (again)

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Message-ID: <20260201140211.GC1964634@ragnatech.se>
Date: Sun, 1 Feb 2026 15:02:11 +0100
From: Niklas Söderlund <niklas.soderlund@...natech.se>
To: Tomi Valkeinen <tomi.valkeinen+renesas@...asonboard.com>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Magnus Damm <magnus.damm@...il.com>,
	Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>,
	Hans Verkuil <hverkuil@...nel.org>, linux-media@...r.kernel.org,
	linux-renesas-soc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] media: renesas: vin: Fix RAW8 (again)

Hi Tomi,

Thanks for really gorking this and making sens of the datasheet, nice 
work!

On 2026-01-27 10:56:12 +0200, Tomi Valkeinen wrote:
> Commit e7376745ad5c ("media: rcar-vin: Fix stride setting for RAW8
> formats") removed dividing the stride by two for RAW8 formats. It is
> unclear how this was tested, but in any of the recent tests this does
> not seem to work and produces quite distorted images.
> 
> However, reverting the patch fixes the issues only partially. VNIS_REG
> requires alignment to 16 bytes, and when dividing the stride by 2, in
> some cases we end up with a non-aligned stride, producing a tilted
> image. This issue has to be fixed in rvin_format_bytesperline() where we
> do the alignment for bytesperline.
> 
> Adding back the stride division and increasing the alignment for RAW8
> formats to 0x20 fixes the problems related to RAW8.
> 
> Fixes: e7376745ad5c ("media: rcar-vin: Fix stride setting for RAW8 formats")
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen+renesas@...asonboard.com>

Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@...natech.se>

> ---
>  drivers/media/platform/renesas/rcar-vin/rcar-dma.c | 22 ++++++++++++++++++++++
>  .../media/platform/renesas/rcar-vin/rcar-v4l2.c    | 12 ++++++++++++
>  2 files changed, 34 insertions(+)
> 
> diff --git a/drivers/media/platform/renesas/rcar-vin/rcar-dma.c b/drivers/media/platform/renesas/rcar-vin/rcar-dma.c
> index b619d1436a41..f9af9177e02f 100644
> --- a/drivers/media/platform/renesas/rcar-vin/rcar-dma.c
> +++ b/drivers/media/platform/renesas/rcar-vin/rcar-dma.c
> @@ -676,8 +676,30 @@ void rvin_crop_scale_comp(struct rvin_dev *vin)
>  	if (vin->scaler)
>  		vin->scaler(vin);
>  
> +	/*
> +	 * VNIS_REG has four lowest bits always 0, i.e. the stride has to be
> +	 * aligned to 16 bytes. This is done in rvin_format_bytesperline().
> +	 */
> +
>  	fmt = rvin_format_from_pixel(vin, vin->format.pixelformat);
>  	stride = vin->format.bytesperline / fmt->bpp;
> +
> +	/*
> +	 * RAW8 format bpp is 1, but the hardware process RAW8 format in 2 pixel
> +	 * units, so we need to divide the stride by 2.
> +	 */
> +	switch (vin->format.pixelformat) {
> +	case V4L2_PIX_FMT_SBGGR8:
> +	case V4L2_PIX_FMT_SGBRG8:
> +	case V4L2_PIX_FMT_SGRBG8:
> +	case V4L2_PIX_FMT_SRGGB8:
> +	case V4L2_PIX_FMT_GREY:
> +		stride /= 2;
> +		break;
> +	default:
> +		break;
> +	}
> +
>  	rvin_write(vin, stride, VNIS_REG);
>  }
>  
> diff --git a/drivers/media/platform/renesas/rcar-vin/rcar-v4l2.c b/drivers/media/platform/renesas/rcar-vin/rcar-v4l2.c
> index 079dbaf016c2..9d45e11898c1 100644
> --- a/drivers/media/platform/renesas/rcar-vin/rcar-v4l2.c
> +++ b/drivers/media/platform/renesas/rcar-vin/rcar-v4l2.c
> @@ -155,6 +155,18 @@ static u32 rvin_format_bytesperline(struct rvin_dev *vin,
>  	case V4L2_PIX_FMT_NV16:
>  		align = 0x20;
>  		break;
> +	case V4L2_PIX_FMT_SBGGR8:
> +	case V4L2_PIX_FMT_SGBRG8:
> +	case V4L2_PIX_FMT_SGRBG8:
> +	case V4L2_PIX_FMT_SRGGB8:
> +	case V4L2_PIX_FMT_GREY:
> +		/*
> +		 * RAW8 format bpp is 1, but the hardware process RAW8 format in
> +		 * 2 pixel units, and we need to align to 32 bytes. See
> +		 * rvin_crop_scale_comp().
> +		 */
> +		align = 0x20;
> +		break;
>  	default:
>  		align = 0x10;
>  		break;
> 
> ---
> base-commit: 7d0a66e4bb9081d75c82ec4957c50034cb0ea449
> change-id: 20260127-rcar-fix-raw8-again-9dacab87ad33
> 
> Best regards,
> -- 
> Tomi Valkeinen <tomi.valkeinen+renesas@...asonboard.com>
> 

-- 
Kind Regards,
Niklas Söderlund