[PATCH v4 10/10] drm/display: hdmi-audio: warn if HDMI connector doesn't support Audio IF

[Maxime Ripard]

On Tue, Sep 09, 2025 at 05:52:08PM +0300, Dmitry Baryshkov wrote:
> Sending Audio InfoFrames is mandatory for getting audio to work over the
> HDMI link. Warn if the driver requests HDMI audio support for the HDMI
> connector, but there is no support for Audio InfoFrames.
> 
> Suggested-by: Maxime Ripard <mripard at kernel.org>
> Acked-by: Daniel Stone <daniels at collabora.com>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at oss.qualcomm.com>
> ---
>  drivers/gpu/drm/display/drm_hdmi_audio_helper.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/gpu/drm/display/drm_hdmi_audio_helper.c b/drivers/gpu/drm/display/drm_hdmi_audio_helper.c
> index 7d78b02c144621de528b40b1425f25e465edd1ae..35e0e79cb683a68af813344aa86c154c3a5531fe 100644
> --- a/drivers/gpu/drm/display/drm_hdmi_audio_helper.c
> +++ b/drivers/gpu/drm/display/drm_hdmi_audio_helper.c
> @@ -10,6 +10,7 @@
>  
>  #include <drm/drm_connector.h>
>  #include <drm/drm_device.h>
> +#include <drm/drm_print.h>
>  #include <drm/display/drm_hdmi_audio_helper.h>
>  
>  #include <sound/hdmi-codec.h>
> @@ -178,6 +179,17 @@ int drm_connector_hdmi_audio_init(struct drm_connector *connector,
>  	    !funcs->shutdown)
>  		return -EINVAL;
>  
> +	if (connector->connector_type == DRM_MODE_CONNECTOR_HDMIA ||
> +	    connector->connector_type == DRM_MODE_CONNECTOR_HDMIB) {
> +		unsigned long supported_infoframes =
> +			connector->hdmi.supported_infoframes;
> +
> +		if (supported_infoframes &&
> +		    !(supported_infoframes & DRM_CONNECTOR_INFOFRAME_AUDIO))
> +			drm_warn(connector->dev, "HDMI Audio with no support for Audio InfoFrames\n");
> +	}
> +
> +

That's not what I suggested. What I suggested was that we tould check
the return code of write_infoframe, and warn if it is set by the
framework, but returns EOPNOTSUPP.

Maxime
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