Re: [PATCH v4 09/10] drm/connector: verify that HDMI connectors support necessary InfoFrames

[Maxime Ripard <mripard@kernel.org>]

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On Tue, Sep 09, 2025 at 05:52:07PM +0300, Dmitry Baryshkov wrote:
> Check that connector initialized by drmm_connector_hdmi_init() supports
> AVI InfoFrames and warn if it doesn't support Vendor-Specific
> InfofRames (HDMI InfoFrames are more or less required).
> 
> Suggested-by: Maxime Ripard <mripard@kernel.org>
> Acked-by: Daniel Stone <daniels@collabora.com>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
> ---
>  drivers/gpu/drm/drm_connector.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
> index 92a75684a0f7375d3a94e8c666cb71064ecc8035..222a0ef66d9fdbdb56108ceeb40e7f369d810350 100644
> --- a/drivers/gpu/drm/drm_connector.c
> +++ b/drivers/gpu/drm/drm_connector.c
> @@ -602,6 +602,13 @@ int drmm_connector_hdmi_init(struct drm_device *dev,
>  	if (!(max_bpc == 8 || max_bpc == 10 || max_bpc == 12))
>  		return -EINVAL;
>  
> +	/* AVI is required */
> +	if (!(supported_infoframes & DRM_CONNECTOR_INFOFRAME_AVI))
> +		return -EINVAL;
> +
> +	if (!(supported_infoframes & DRM_CONNECTOR_INFOFRAME_VENDOR))
> +		drm_info(dev, "HDMI connector with no support for Vendor-Specific InfoFrame\n");
> +

Same remark than on patch 10. It's not something we can check at init
time, and we should check (and document!) that if we expect an infoframe
to be written but the write_infoframe hook doesn't support it, it's an
error.

Maxime

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