[PATCH 1/7] drm/vc4: hdmi: Check that the monitor supports HDMI audio

[Paul Kocialkowski]

Hi,

On Mon, 2019-03-04 at 15:52 +0100, Maxime Ripard wrote:
> The current code assumes as soon as the device is an HDMI one that it
> supports an audio sink. However, strictly speaking, this is exposed as a
> separate part of EDID.
> 
> This can be checked through the drm_detect_monitor_audio function, so let's
> use it and make sure that we can use the HDMI monitor as an output before
> sending sound.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard at bootlin.com>

Reviewed-by: Paul Kocialkowski <paul.kocialkowski at bootlin.com>

Cheers,

Paul

> ---
>  drivers/gpu/drm/vc4/vc4_hdmi.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index 88fd5df7e7dc..a1bdc065c47c 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -109,6 +109,7 @@ struct vc4_hdmi_encoder {
>  	struct vc4_encoder base;
>  	bool hdmi_monitor;
>  	bool limited_rgb_range;
> +	bool monitor_has_audio;
>  };
>  
>  static inline struct vc4_hdmi_encoder *
> @@ -278,6 +279,7 @@ static int vc4_hdmi_connector_get_modes(struct drm_connector *connector)
>  		return -ENODEV;
>  
>  	vc4_encoder->hdmi_monitor = drm_detect_hdmi_monitor(edid);
> +	vc4_encoder->monitor_has_audio = drm_detect_monitor_audio(edid);
>  
>  	drm_connector_update_edid_property(connector, edid);
>  	ret = drm_add_edid_modes(connector, edid);
> @@ -785,9 +787,13 @@ static int vc4_hdmi_audio_startup(struct snd_pcm_substream *substream,
>  {
>  	struct vc4_hdmi *hdmi = dai_to_hdmi(dai);
>  	struct drm_encoder *encoder = hdmi->encoder;
> +	struct vc4_hdmi_encoder *vc4_encoder = to_vc4_hdmi_encoder(encoder);
>  	struct vc4_dev *vc4 = to_vc4_dev(encoder->dev);
>  	int ret;
>  
> +	if (!vc4_encoder->monitor_has_audio)
> +		return -ENODEV;
> +
>  	if (hdmi->audio.substream && hdmi->audio.substream != substream)
>  		return -EINVAL;
>  
-- 
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com