> config SND_SOC_QDSP6_APM > select SND_SOC_QDSP6_APM_DAI > + select SND_SOC_QDSP6_APM_LPASS_DAI > tristate tristate then select? > > +static int q6apm_lpass_dai_prepare(struct snd_pcm_substream *substream, > + struct snd_soc_dai *dai) > +{ > + struct q6apm_lpass_dai_data *dai_data = dev_get_drvdata(dai->dev); > + struct audioreach_module_config *cfg = &dai_data->module_config[dai->id]; > + int graph_id = dai->id; > + int rc; > + struct q6apm_graph *graph; > + > + if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) { > + graph = q6apm_graph_open(dai->dev, NULL, dai->dev, graph_id); > + if (IS_ERR(graph)) { > + dev_err(dai->dev, "Failed to open graph (%d)\n", > + graph_id); > + rc = PTR_ERR(graph); > + return rc; > + } > + dai_data->graph[graph_id] = graph; > + } so you don't open a graph on capture? How does the rest work if dai_data->graph is not initialized? Or is it done somewhere else and it'd be worthy of a comment? > + > + cfg->direction = substream->stream; > + rc = q6apm_graph_media_format_pcm(dai_data->graph[dai->id], cfg); > + > + if (rc) { > + dev_err(dai->dev, "Failed to set media format %d\n", rc); > + return rc; > + } > + > + rc = q6apm_graph_prepare(dai_data->graph[dai->id]); > + if (rc) { > + dev_err(dai->dev, "Failed to prepare Graph %d\n", rc); > + return rc; > + } > + > + rc = q6apm_graph_start(dai_data->graph[dai->id]); > + if (rc < 0) { > + dev_err(dai->dev, "fail to start APM port %x\n", dai->id); > + return rc; > + } > + dai_data->is_port_started[dai->id] = true; > + > + return 0; > +} > + > +static int q6apm_lpass_dai_startup(struct snd_pcm_substream *substream, > + struct snd_soc_dai *dai) > +{ > + struct q6apm_lpass_dai_data *dai_data = dev_get_drvdata(dai->dev); > + int graph_id = dai->id; > + struct q6apm_graph *graph; > + > + if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) { > + graph = q6apm_graph_open(dai->dev, NULL, dai->dev, graph_id); > + if (IS_ERR(graph)) { > + dev_err(dai->dev, "Failed to open graph (%d)\n", > + graph_id); > + return PTR_ERR(graph); > + } > + dai_data->graph[graph_id] = graph; > + } definitively need a comment on why the behavior is different from capture and playback? What prevents you from doing the same operations in .startup for capture and playback? > + > + return 0; > +} > +