Re: [PATCH v6 08/13] drm/imx: dc-ed: Support getting source selection

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Missing error check for regmap_read() leads to potential use of uninitialized variable 'val'.
--

commit 9ce4a83e3feed66ffe4fb2913d0e30db41ffaf27
Author: Liu Ying <victor.liu@nxp.com>

drm/imx: dc-ed: Support getting source selection

This commit adds a helper to get ExtDst source selection. This functionality is
intended to support disabling CRTC at boot in a subsequent commit.

> diff --git a/drivers/gpu/drm/imx/dc/dc-ed.c b/drivers/gpu/drm/imx/dc/dc-ed.c
> index de1b71315eabd..b8ab41271bb40 100644
> --- a/drivers/gpu/drm/imx/dc/dc-ed.c
> +++ b/drivers/gpu/drm/imx/dc/dc-ed.c
> @@ -149,6 +149,32 @@ void dc_ed_pec_src_sel(struct dc_ed *ed, enum dc_link_id src)
>  	}
>  }
>  
> +int dc_ed_pec_src_sel_get(struct dc_ed *ed, enum dc_link_id *src)
> +{
> +	u32 val;
> +
> +	regmap_read(ed->reg_pec, PIXENGCFG_DYNAMIC, &val);

[Severity: Medium]
If regmap_read() fails due to an underlying I/O or bus error, it will return
a negative error code and leave the stack variable 'val' uninitialized. The
subsequent switch statement would then evaluate this uninitialized memory.

If 'val' happens to randomly match one of the LINK_ID_* cases, the function
could return success (0) and pass back a garbage source selection,
potentially causing incorrect display configuration or state corruption.

Should this code check the return value of regmap_read() to avoid using an
uninitialized 'val'?

> +
> +	switch (val) {
> +	case LINK_ID_NONE:
> +	case LINK_ID_CONSTFRAME0:

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260904-imx8-dc-prefetch-v6-0-26643e3f6cb7@nxp.com?part=8