On 1/12/23 00:58, Chancel Liu wrote:

The commit 1da681e52853 ("ASoC: soc-pcm.c: Clear DAIs parameters after stream_active is updated") tries to make sure DAIs parameters can be cleared properly through moving the cleanup to the place where stream_active is updated. However, it will cause the cleanup only happening in soc_pcm_close().

Suppose a case: aplay -Dhw:0 44100.wav 48000.wav. The case calls soc_pcm_open()->soc_pcm_hw_params()->soc_pcm_hw_free()-> soc_pcm_hw_params()->soc_pcm_hw_free()->soc_pcm_close() in order. The parameters would be remained in the system even if the playback of 44100.wav is finished.

The case requires us clearing parameters in phase of soc_pcm_hw_free(). We shouldn't use stream_active to decide if we must do the cleanup since it is finally updated in soc_pcm_close().

This patch introduces a usage count called hw_params_count in snd_soc_dai structure. It records the times of setting parameters to this DAI then decreases each time soc_pcm_hw_free() is called. If the count decreases to 0, it means this DAI is not used now and we should clear the parameters.

what makes you think that the use of hw_params and hw_free is symmetrical?

A couple of years ago we found a case where the FE hw_params failed, and in that case the BE hw_free was called without the BE hw_params ever being invoked first. This is due to the DPCM error handling, and as a result all our hw_free implementations test if the resources are actually allocated/valid and never assume hw_params was used.

IIRC it's also valid to call hw_params multiple times without calling hw_free every time.

Fixes: 1da681e52853 ("ASoC: soc-pcm.c: Clear DAIs parameters after stream_active is updated")

Signed-off-by: Chancel Liu chancel.liu@nxp.com

include/sound/soc-dai.h | 3 +++ sound/soc/soc-pcm.c | 16 +++++++++++----- 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/include/sound/soc-dai.h b/include/sound/soc-dai.h index ea7509672086..a7e589a0fe72 100644 --- a/include/sound/soc-dai.h +++ b/include/sound/soc-dai.h @@ -451,6 +451,9 @@ struct snd_soc_dai { unsigned int channels; unsigned int sample_bits;

• /* Count of setting DAI parameters */
• unsigned int hw_params_count;
• /* parent platform/codec */ struct snd_soc_component *component;

diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c index 579a44d81d9a..2c2a5dcf9e06 100644 --- a/sound/soc/soc-pcm.c +++ b/sound/soc/soc-pcm.c @@ -711,14 +711,10 @@ static int soc_pcm_clean(struct snd_soc_pcm_runtime *rtd,

if (!rollback) { snd_soc_runtime_deactivate(rtd, substream->stream);

• /* clear the corresponding DAIs parameters when going to be inactive */
  

• for_each_rtd_dais(rtd, i, dai) {
  

• 	if (snd_soc_dai_active(dai) == 0)
  

• 		soc_pcm_set_dai_params(dai, NULL);
  
  

• for_each_rtd_dais(rtd, i, dai)
  if (snd_soc_dai_stream_active(dai, substream->stream) == 0)
  	snd_soc_dai_digital_mute(dai, 1, substream->stream);
  

• }
  

  }

  for_each_rtd_dais(rtd, i, dai)

@@ -949,6 +945,14 @@ static int soc_pcm_hw_clean(struct snd_soc_pcm_runtime *rtd,

snd_soc_dpcm_mutex_assert_held(rtd);

• /* clear the corresponding DAIs parameters when hw_params_count decreases to 0 */
• for_each_rtd_dais(rtd, i, dai)

• if (snd_soc_dai_stream_valid(dai, substream->stream)) {
  

• 	dai->hw_params_count--;
  

• 	if (dai->hw_params_count == 0)
  

• 		soc_pcm_set_dai_params(dai, NULL);
  

• }
  

• /* run the stream event */ snd_soc_dapm_stream_stop(rtd, substream->stream);

@@ -1051,6 +1055,7 @@ static int __soc_pcm_hw_params(struct snd_soc_pcm_runtime *rtd,

soc_pcm_set_dai_params(codec_dai, &codec_params);
snd_soc_dapm_update_dai(substream, &codec_params, codec_dai);

• codec_dai->hw_params_count++;
  

  }

  for_each_rtd_cpu_dais(rtd, i, cpu_dai) {

@@ -1068,6 +1073,7 @@ static int __soc_pcm_hw_params(struct snd_soc_pcm_runtime *rtd, /* store the parameters for each DAI */ soc_pcm_set_dai_params(cpu_dai, params); snd_soc_dapm_update_dai(substream, params, cpu_dai);

• cpu_dai->hw_params_count++;
  

  }

  ret = snd_soc_pcm_component_hw_params(substream, params);