Re: [RFC] soc_pcm_open: error path behavior change since v5.6

7 Sep 2020


      Hi Cezary
...
static int soc_pcm_open(struct snd_pcm_substream *substream)
{
(...)
/* startup the audio subsystem */
   for_each_rtd_dais(rtd, i, dai) {
   	ret = snd_soc_dai_startup(dai, substream);
   	if (ret < 0) {
   		dev_err(dai->dev,
   			"ASoC: can't open DAI %s: %d\n",
   			dai->name, ret);
   		goto config_err;
   	}
if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
	dai->tx_mask = 0;
else
	dai->rx_mask = 0;

}
(...)
config_err:
   for_each_rtd_dais(rtd, i, dai)
   	snd_soc_dai_shutdown(dai, substream);


Let's assume we have 10 dais. In newer kernels, if
snd_soc_dai_startup() fails at i=5, error path will attempt to perform
snd_soc_dai_shutdown() for all dais (all 10) regardless if respective
dai was opened or not. This is a clear behavior change when compared
to v5.6 where cpu_dai was cleaned-up only if it was previously started
successfully. Due to usage of for_each_rtd_codec_dai_rollback macro,
the same applies to codec_dais.
Oh, yes. We need _rollback() for it.
I will try to fix it
Thank you for your help !!
Best regards
---
Kuninori Morimoto