Re: [PATCH v3 09/11] drm/bridge: imx8mp-hdmi-tx-connector-fixup: show a warning when adding the overlay

[Liu Ying <victor.liu@nxp.com>]

On Thu, Apr 02, 2026 at 11:26:04AM +0200, Luca Ceresoli wrote:
> Describing the HDMI connector in device tree is recommended. While the
> overlay insertion is a workaround to avoid breaking existing devices, every
> dts should be improved by adding a connector description.
> 
> Add a warning to make users aware as far as possible.
> 
> As a warning line cannot hold all the relevant info, add a detailed comment
> in the code so it easy to find when the warning is seen.
> 
> Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
> 
> ---
> 
> Patch added in v3. Kept as a separate comment w.r.t. the patch adding the
> overlay to let it be added in a later moment in case we want to convert
> existing dts files before adding the warning.
> ---
>  .../gpu/drm/bridge/imx/imx8mp-hdmi-tx-connector-fixup.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/drivers/gpu/drm/bridge/imx/imx8mp-hdmi-tx-connector-fixup.c b/drivers/gpu/drm/bridge/imx/imx8mp-hdmi-tx-connector-fixup.c
> index dc1736bfc3ac..f6190d86abd0 100644
> --- a/drivers/gpu/drm/bridge/imx/imx8mp-hdmi-tx-connector-fixup.c
> +++ b/drivers/gpu/drm/bridge/imx/imx8mp-hdmi-tx-connector-fixup.c
> @@ -44,6 +44,23 @@ static int __init imx8mp_hdmi_tx_connector_fixup_init(void)
>  	if (endpoint)
>  		return 0;
>  
> +	/*
> +	 * Boards with an HDMI connector should describe it in a device
> +	 * tree node with compatible = "hdmi-connector".
> +	 *
> +	 * If you see this warning, it means such a node was not found and
> +	 * a fallback one is added using a device tree overlay. Please add
> +	 * one in your device tree, also describing the exact connector
> +	 * type (the added overlay assumes Type A as a fallback, but it
> +	 * might be wrong).
> +	 *
> +	 * This node is necessary for modern DRM, where bridge drivers do
> +	 * not create a connector (see the DRM_BRIDGE_ATTACH_NO_CONNECTOR
> +	 * flag). See https://docs.kernel.org/gpu/drm-kms-helpers.html for
> +	 * more info.
> +	 */
> +	pr_warn("Please add a hdmi-connector DT node for imx8mp-hdmi-tx.");

Missing '\n' in warning message.  With it added:
Reviewed-by: Liu Ying <victor.liu@nxp.com>

> +
>  	dtbo_start = __dtbo_imx8mp_hdmi_tx_connector_fixup_begin;
>  	dtbo_size = __dtbo_imx8mp_hdmi_tx_connector_fixup_end -
>  		    __dtbo_imx8mp_hdmi_tx_connector_fixup_begin;
> 

-- 
Regards,
Liu Ying