ASoC: OMAP: HDMI: Improve how the display state is verified

Before starting to play audio, we need to make sure that the
display is active and the current video mode supports audio. instead
of using the overlay manager in the machine driver, we use the DSS audio
interface's audio_supported function. As we already have a pointer to
the correct dssdev, we do not have to look for it every time audio is
to be played. Also, the CPU DAI startup function is called earlier
than the card hw_param function. Hence and we can detect the state of
the display earlier.

While there, add a error message if the constraint cannot be applied.

Signed-off-by: Ricardo Neri <ricardo.neri@ti.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

squash to improve err
Signed-off-by: Liam Girdwood <lrg@ti.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/sound/soc/omap/omap-hdmi.c b/sound/soc/omap/omap-hdmi.c
index fc4815a..ec7c7e6 100644
--- a/sound/soc/omap/omap-hdmi.c
+++ b/sound/soc/omap/omap-hdmi.c
@@ -51,6 +51,7 @@ struct hdmi_priv {
 static int omap_hdmi_dai_startup(struct snd_pcm_substream *substream,
 				  struct snd_soc_dai *dai)
 {
+	struct hdmi_priv *priv = snd_soc_dai_get_drvdata(dai);
 	int err;
 	/*
 	 * Make sure that the period bytes are multiple of the DMA packet size.
@@ -58,9 +59,15 @@ static int omap_hdmi_dai_startup(struct snd_pcm_substream *substream,
 	 */
 	err = snd_pcm_hw_constraint_step(substream->runtime, 0,
 				 SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 128);
-	if (err < 0)
+	if (err < 0) {
+		dev_err(dai->dev, "could not apply constraint\n");
 		return err;
+	}
 
+	if (!priv->dssdev->driver->audio_supported(priv->dssdev)) {
+		dev_err(dai->dev, "audio not supported\n");
+		return -ENODEV;
+	}
 	return 0;
 }