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