On Tue, 2015-11-10 at 09:12 -0800, Caleb Crome wrote:
> Hi again,
> I have a system that has separate DACs and ADCs, as opposed to
> bidirectional CODECS.
>
> The ADCs have a snd_soc_dai_driver structure that have a .capture
> field defined with a .rates parameter, and the DACs have a
> snd_soc_dai_driver structure that have a .playback field defined with
> a .rates parameter.
>
> However, the ADCs have no .playback.rates, and the DACs have no
> .capture.rates. Even though the ADC can record at a given rate and the
> DAC can play at that same rate, the soc_pcm_init_runtime_hw function
> calculates the rates in this loop:
>
> ------------------------------
> /* first calculate min/max only for CODECs in the DAI link */
> for (i = 0; i < rtd->num_codecs; i++) {
> codec_dai_drv = rtd->codec_dais[i]->driver;
> if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
> codec_stream = &codec_dai_drv->playback;
> else
> codec_stream = &codec_dai_drv->capture;
> chan_min = max(chan_min, codec_stream->channels_min);
> chan_max = min(chan_max, codec_stream->channels_max);
> rate_min = max(rate_min, codec_stream->rate_min);
> rate_max = min_not_zero(rate_max, codec_stream->rate_max);
> formats &= codec_stream->formats;
> rates = snd_pcm_rate_mask_intersect(codec_stream->rates, rates);
> }
> ------------------------------
>
> which can't work out that one side is play only and the other is
> record only, yet they do in fact have matching rates. So, I get a "no
> matching channels" error.
>
>
> Here are my example drivers declarations:
> for the ADC:
> ----------------------
> static struct snd_soc_dai_driver cs53l30_dai = {
> .name = "cs53l30-hifi",
> .capture = {
> .stream_name = "Capture",
> .channels_min = 4,
> .channels_max = 16,
> .rates = SNDRV_PCM_RATE_16000,
> .formats =SNDRV_PCM_FMTBIT_S16_LE,
> },
> };
> --------------------
>
> and for the DAC
>
> ----------------------
> static struct snd_soc_dai_driver tlv320dac3100_dai = {
> .name = "tlv320dac3100-hifi",
> .playback = {
> .stream_name = "Playback",
> .channels_min = 2,
> .channels_max = 16,
> .rates = SNDRV_PCM_RATE_16000,
> .formats =SNDRV_PCM_FMTBIT_S16_LE,
> },
> .ops = &tlv320dac3100_dai_ops,
> };
> ------------------------------
>
> I was able to fake it out by adding a .playback field to my ADC with 0
> channels, and a .capture field to my DAC with 0 channels.
>
> My question is: what's the right way to manage this? I assume we
> should probably tweak soc_pcm_init_runtime_hw, right?
Not sure why this is not working for you. There are other DAI drivers
upstream that are unidirectional and work fine.
Are you combining both unidirectional DAIs above into a single
bidirectional DAI ?
Liam
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