Re: [PATCH v21 09/39] ASoC: qcom: qdsp6: Introduce USB AFE port to q6dsp

[Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>]

>  static struct snd_soc_dai_driver q6dsp_audio_fe_dais[] = {
> +	{
> +		.playback = {
> +			.stream_name = "USB Playback",
> +			.rates = SNDRV_PCM_RATE_8000 | SNDRV_PCM_RATE_11025 |
> +					SNDRV_PCM_RATE_16000 | SNDRV_PCM_RATE_22050 |
> +					SNDRV_PCM_RATE_32000 | SNDRV_PCM_RATE_44100 |
> +					SNDRV_PCM_RATE_48000 | SNDRV_PCM_RATE_96000 |
> +					SNDRV_PCM_RATE_192000,
> +			.formats = SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE |
> +					SNDRV_PCM_FMTBIT_U16_LE | SNDRV_PCM_FMTBIT_U16_BE |
> +					SNDRV_PCM_FMTBIT_S24_LE | SNDRV_PCM_FMTBIT_S24_BE |
> +					SNDRV_PCM_FMTBIT_U24_LE | SNDRV_PCM_FMTBIT_U24_BE,
> +			.channels_min = 1,
> +			.channels_max = 2,
> +			.rate_min =	8000,
> +			.rate_max = 192000,
> +		},
> +		.id = USB_RX,
> +		.name = "USB_RX",
> +	},

Wait, is this saying you will have exactly one PCM device/FE DAI
connected to the USB BE DAI exposed in patch 11?

> +	SND_SOC_DAPM_MIXER("USB Mixer", SND_SOC_NOPM, 0, 0,
> +			   usb_mixer_controls,
> +			   ARRAY_SIZE(usb_mixer_controls)),
> +

And then what is the role of the USB mixer if you only have one input?

I must be missing something.