linux-kernel - Re: [PATCH v2 1/2] media: rkisp1-isp: Set correct data mode for YUV bypass

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20260206001708.GD1376807@killaraus.ideasonboard.com>
Date: Fri, 6 Feb 2026 02:17:08 +0200
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Isaac Scott <isaac.scott@...asonboard.com>
Cc: linux-media@...r.kernel.org, dafna@...tmail.com, mchehab@...nel.org,
	heiko@...ech.de, linux-rockchip@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] media: rkisp1-isp: Set correct data mode for YUV
 bypass

Hi Isaac,

Thank you for the patch.

On Thu, Feb 05, 2026 at 10:32:06AM +0000, Isaac Scott wrote:
> The rkisp1 features a 'bypass' mode for RAW and YUV formats. This
> disables all ISP blocks, and makes the rkisp1 display input data from
> the MIPI CSI receiver at the output, unmodified.
> 
> To determine whether we can activate bypass, we can detect whether both
> the source and sink formats are YUV. If they are, we must configure the
> ISP to expect a YUV input, interpreting H/VSYNC signals as data
> enable / disable.
> 
> Signed-off-by: Isaac Scott <isaac.scott@...asonboard.com>
> 
> ---
> 
> Changelog since v1:
> - Removed in_bypass flag
> - Renamed the patch to better represent the functionality of the patch
> 
> ---
>  drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> index 2311672cedb1..21bfa0edbaf1 100644
> --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-isp.c
> @@ -240,7 +240,9 @@ static int rkisp1_config_isp(struct rkisp1_isp *isp,
>  		}
>  	} else if (sink_fmt->pixel_enc == V4L2_PIXEL_ENC_YUV) {
>  		acq_mult = 2;
> -		if (mbus_type == V4L2_MBUS_CSI2_DPHY) {
> +		if (src_fmt->pixel_enc == V4L2_PIXEL_ENC_YUV) {
> +			isp_ctrl = RKISP1_CIF_ISP_CTRL_ISP_MODE_DATA_MODE;
> +		} else if (mbus_type == V4L2_MBUS_CSI2_DPHY) {
>  			isp_ctrl = RKISP1_CIF_ISP_CTRL_ISP_MODE_ITU601;
>  		} else {
>  			if (mbus_type == V4L2_MBUS_BT656)

This doesn't seem right. If the sink format is YUV, then the source
format has to be YUV too (the ISP can't produce Bayer from YUV). The
source pixel encoding condition will always be true, the other branches
will never be taken, most likely breaking parallel inputs.

Also, the documentation states that in YCbCr bypass mode, ISP_MODE
should be set to 2 (ITU-R BT.601), not 4 (data mode).

-- 
Regards,

Laurent Pinchart