Re: [PATCH 4/4] drm/bridge: tc358767: do not open-code devm_drm_of_get_bridge in DSI path

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Probe fails with -ENODEV when port 2 has no downstream panel or bridge defined, breaking DisplayPort output.
--

commit 70b94894718399f191075561feb4f2f4f31b4aa9
Author: Alexander Stein <alexander.stein@ew.tq-group.com>

drm/bridge: tc358767: do not open-code devm_drm_of_get_bridge in DSI path

This commit replaces the open-coded panel/bridge discovery logic
with devm_drm_of_get_bridge() to simplify the probing code path
in the tc358767 bridge driver.

> diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
> --- a/drivers/gpu/drm/bridge/tc358767.c
> +++ b/drivers/gpu/drm/bridge/tc358767.c
[ ... ]
> @@ -2341,28 +2341,22 @@ static int tc_probe_edp_bridge_endpoint(struct tc_data *tc)
>  {
>  	struct device *dev = tc->dev;
>  	struct drm_bridge *bridge;
> -	struct drm_panel *panel;
>  	int ret;
>  
>  	/* port@2 is the output port */
> -	ret = drm_of_find_panel_or_bridge(dev->of_node, 2, 0, &panel, &bridge);
> -	if (ret && ret != -ENODEV)
> -		return dev_err_probe(dev, ret,
> -				     "Could not find DSI panel or bridge\n");
> -
> -	if (panel) {
> -		struct drm_bridge *panel_bridge;
> -
> -		panel_bridge = devm_drm_panel_bridge_add(dev, panel);
> -		if (IS_ERR(panel_bridge))
> -			return PTR_ERR(panel_bridge);
> -
> -		tc->panel_bridge = panel_bridge;
> -		tc->bridge.type = DRM_MODE_CONNECTOR_eDP;
> -	} else {
> -		tc->bridge.type = DRM_MODE_CONNECTOR_DisplayPort;
> +	bridge = devm_drm_of_get_bridge(dev, dev->of_node, 2, 0);
> +	if (IS_ERR(bridge)) {
> +		ret = PTR_ERR(bridge);
> +		if (ret != -ENODEV)
> +			return dev_err_probe(dev, ret,
> +					     "Could not find DSI panel or bridge\n");
> +		else
> +			return ret;

[Severity: High]
Does this break the probe sequence for DisplayPort configurations?

The previous code in tc_probe_edp_bridge_endpoint() allowed -ENODEV
to bypass the early return, falling back to setting the bridge type to
DRM_MODE_CONNECTOR_DisplayPort when no panel or bridge was found.

By explicitly returning ret when it equals -ENODEV, probe is now aborted
if the downstream device isn't fixed in the device tree. Could this cause
the DisplayPort/eDP bridge driver to fail to load on valid hardware setups?

>  	}
>  
> +	tc->panel_bridge = bridge;
> +	tc->bridge.type = bridge->type;
> +
>  	if (tc->hpd_pin >= 0)
>  		tc->bridge.ops |= DRM_BRIDGE_OP_DETECT;
>  	tc->bridge.ops |= DRM_BRIDGE_OP_EDID;

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260624121515.2301219-1-alexander.stein@ew.tq-group.com?part=4