[alsa-devel] [PATCH v6] ASoC: Apply msbits constraint for sample size bigger than the msbits

[Peter Ujfalusi]

In order to avoid confusing the applications with msbits bigger
than the selected sample size apply the msbits constraint only
to sample size bigger than the requested msbits.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi at ti.com>
---
Hi Mark,

Let's try this way.
I think this implementation is quete clear for the first look to understand what
it is doing.

Regards,
Peter

 sound/soc/soc-pcm.c |   23 +++++++++++++++--------
 1 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index 8bb1793..d6fdde2 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -68,7 +68,7 @@ static int soc_pcm_apply_symmetry(struct snd_pcm_substream *substream,
  * like the DAC/ADC resolution to use but there isn't right now.
  */
 static int sample_sizes[] = {
-	8, 16, 24, 32,
+	32, 24, 16, 8,
 };
 
 static void soc_pcm_apply_msb(struct snd_pcm_substream *substream,
@@ -85,13 +85,20 @@ static void soc_pcm_apply_msb(struct snd_pcm_substream *substream,
 		return;
 
 	for (i = 0; i < ARRAY_SIZE(sample_sizes); i++) {
-		ret = snd_pcm_hw_constraint_msbits(substream->runtime,
-						   0, sample_sizes[i],
-						   bits);
-		if (ret != 0)
-			dev_warn(dai->dev,
-				 "Failed to set MSB %d/%d: %d\n",
-				 bits, sample_sizes[i], ret);
+		if (sample_sizes[i] > bits) {
+			ret = snd_pcm_hw_constraint_msbits(substream->runtime,
+						      0, sample_sizes[i], bits);
+			if (ret != 0)
+				dev_warn(dai->dev,
+					 "Failed to set MSB %d/%d: %d\n",
+					 bits, sample_sizes[i], ret);
+		} else {
+			/*
+			 * The remaining sample sizes are smaller than the
+			 * requested msbits, we can bail out from the loop.
+			 */
+			break;
+		}
 	}
 }
 
-- 
1.7.8.3