[PATCH v4 2/3] drm/bridge: analogix_dp: Add validation for samsung,lane-count property

[Luca Ceresoli]

On Fri, 29 May 2026 12:05:29 +0800, Damon Ding <damon.ding at rock-chips.com> wrote:

Hello Damon,

>
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index 8cf6b73bceac..699a7f380c56 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -1260,8 +1261,16 @@ static int analogix_dp_dt_parse_pdata(struct analogix_dp_device *dp)
>  		 */
>  		of_property_read_u32(dp_node, "samsung,link-rate",
>  				     &video_info->max_link_rate);
> -		of_property_read_u32(dp_node, "samsung,lane-count",
> -				     &video_info->max_lane_count);
> +		ret = of_property_read_u32(dp_node, "samsung,lane-count",
> +					   &video_info->max_lane_count);
> +		if (!ret) {
> +			if (video_info->max_lane_count == 0 ||
> +			    video_info->max_lane_count > LANE_COUNT4) {

This sashiko report seems to me valid.

But I'n no DP expert, I have no idea whether this ther one is valid.

> +				dev_err(dp->dev, "samsung,lane-count = %d is out of range\n",
> +					video_info->max_lane_count);
> +				return -EINVAL;
> +			}
> +		}

As reported by sashiko, 'count == 0' should be 'count <= 0', being an enum.

Additionally I'd avoid the nested if, and I think using dev_err_probe() is
correct here (we are only called by probe functions), so it all could
become:

   if (ret || count <= 0 || count > LANE_COUNT0)
        return dev_err_probe(...);

There are other sashiko reports to patch 3, and at least one seems valid to
me. Can you either fix them in the next iteration or elaborate on why the
code is correct there?

Thanks!

-- 
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com