drm/vc4: hdmi: Reset audio infoframe on encoder_enable if previously streaming

If the encoder is disabled and re-enabled (eg mode change) all infoframes
are reset, whilst the audio subsystem know nothing about this change.
The driver therefore needs to reinstate the audio infoframe for
itself.
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Tested-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Link: https://patchwork.freedesktop.org/patch/msgid/cd579ccc2c9b9d2fce0ebaf32f847cedb0e4a7a2.1599120059.git-series.maxime@cerno.tech

drivers/gpu/drm/vc4/vc4_hdmi.c

@@ -308,8 +308,16 @@ static void vc4_hdmi_set_audio_infoframe(struct drm_encoder *encoder)
 
 static void vc4_hdmi_set_infoframes(struct drm_encoder *encoder)
 {
+	struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
+
 	vc4_hdmi_set_avi_infoframe(encoder);
 	vc4_hdmi_set_spd_infoframe(encoder);
+	/*
+	 * If audio was streaming, then we need to reenabled the audio
+	 * infoframe here during encoder_enable.
+	 */
+	if (vc4_hdmi->audio.streaming)
+		vc4_hdmi_set_audio_infoframe(encoder);
 }
 
 static void vc4_hdmi_encoder_disable(struct drm_encoder *encoder)
@@ -694,6 +702,7 @@ static void vc4_hdmi_audio_reset(struct vc4_hdmi *vc4_hdmi)
 	struct device *dev = &vc4_hdmi->pdev->dev;
 	int ret;
 
+	vc4_hdmi->audio.streaming = false;
 	ret = vc4_hdmi_stop_packet(encoder, HDMI_INFOFRAME_TYPE_AUDIO);
 	if (ret)
 		dev_err(dev, "Failed to stop audio infoframe: %d\n", ret);
@@ -797,6 +806,7 @@ static int vc4_hdmi_audio_trigger(struct snd_pcm_substream *substream, int cmd,
 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 		vc4_hdmi_set_audio_infoframe(encoder);
+		vc4_hdmi->audio.streaming = true;
 
 		if (vc4_hdmi->variant->phy_rng_enable)
 			vc4_hdmi->variant->phy_rng_enable(vc4_hdmi);
@@ -815,6 +825,8 @@ static int vc4_hdmi_audio_trigger(struct snd_pcm_substream *substream, int cmd,
 		if (vc4_hdmi->variant->phy_rng_disable)
 			vc4_hdmi->variant->phy_rng_disable(vc4_hdmi);
 
+		vc4_hdmi->audio.streaming = false;
+
 		break;
 	default:
 		break;

drivers/gpu/drm/vc4/vc4_hdmi.h

@@ -85,6 +85,8 @@ struct vc4_hdmi_audio {
 	int channels;
 	struct snd_dmaengine_dai_dma_data dma_data;
 	struct snd_pcm_substream *substream;
+
+	bool streaming;
 };
 
 /* General HDMI hardware state. */