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

[Maxime Ripard]

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>
---
 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;
 
-- 
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