Re: [alsa-devel] [PATCH 3/3] ASoC: fsl_asrc: Fix error with S24_3LE format bitstream in i.MX8

On Mon, Sep 09, 2019 at 06:33:21PM -0400, Shengjiu Wang wrote:

There is error "aplay: pcm_write:2023: write error: Input/output error" on i.MX8QM/i.MX8QXP platform for S24_3LE format.

In i.MX8QM/i.MX8QXP, the DMA is EDMA, which don't support 24bit sample, but we didn't add any constraint, that cause issues.

So we need to query the caps of dma, then update the hw parameters according to the caps.

@@ -285,8 +293,81 @@ static int fsl_asrc_dma_startup(struct snd_pcm_substream *substream)

runtime->private_data = pair;

• snd_pcm_hw_constraint_integer(substream->runtime,

• 		      SNDRV_PCM_HW_PARAM_PERIODS);
  

• ret = snd_pcm_hw_constraint_integer(substream->runtime,

• 			    SNDRV_PCM_HW_PARAM_PERIODS);
  

• if (ret < 0) {

• dev_err(dev, "failed to set pcm hw params periods\n");
  

• return ret;
  

• }
• dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
• /* Request a temp pair, which is release in the end */
• fsl_asrc_request_pair(1, pair);

Not sure if it'd be practical, but a pair request could fail. Will probably need to check return value.

And a quick feeling is that below code is mostly identical to what is in the soc-generic-dmaengine-pcm.c file. So I'm wondering if we could abstract a helper function somewhere in the ASoC core: Mark?

Thanks Nicolin

• tmp_chan = fsl_asrc_get_dma_channel(pair, dir);

• if (!tmp_chan) {

• dev_err(dev, "can't get dma channel\n");
  

• return -EINVAL;
  

• }

• ret = dma_get_slave_caps(tmp_chan, &dma_caps);

• if (ret == 0) {

• if (dma_caps.cmd_pause)
  

• 	snd_imx_hardware.info |= SNDRV_PCM_INFO_PAUSE |
  

• 				 SNDRV_PCM_INFO_RESUME;
  

• if (dma_caps.residue_granularity <=
  

• 	DMA_RESIDUE_GRANULARITY_SEGMENT)
  

• 	snd_imx_hardware.info |= SNDRV_PCM_INFO_BATCH;
  

• if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
  

• 	addr_widths = dma_caps.dst_addr_widths;
  

• else
  

• 	addr_widths = dma_caps.src_addr_widths;
  

• }

• /*

• * If SND_DMAENGINE_PCM_DAI_FLAG_PACK is set keep
  

• * hw.formats set to 0, meaning no restrictions are in place.
  

• * In this case it's the responsibility of the DAI driver to
  

• * provide the supported format information.
  

• */
  

• if (!(dma_data->flags & SND_DMAENGINE_PCM_DAI_FLAG_PACK))

• /*
  

•  * Prepare formats mask for valid/allowed sample types. If the
  

•  * dma does not have support for the given physical word size,
  

•  * it needs to be masked out so user space can not use the
  

•  * format which produces corrupted audio.
  

•  * In case the dma driver does not implement the slave_caps the
  

•  * default assumption is that it supports 1, 2 and 4 bytes
  

•  * widths.
  

•  */
  

• for (i = 0; i <= SNDRV_PCM_FORMAT_LAST; i++) {
  

• 	int bits = snd_pcm_format_physical_width(i);
  

• 	/*
  

• 	 * Enable only samples with DMA supported physical
  

• 	 * widths
  

• 	 */
  

• 	switch (bits) {
  

• 	case 8:
  

• 	case 16:
  

• 	case 24:
  

• 	case 32:
  

• 	case 64:
  

• 		if (addr_widths & (1 << (bits / 8)))
  

• 			snd_imx_hardware.formats |= (1LL << i);
  

• 		break;
  

• 	default:
  

• 		/* Unsupported types */
  

• 		break;
  

• 	}
  

• }
  

• if (tmp_chan)

• dma_release_channel(tmp_chan);
  

• fsl_asrc_release_pair(pair);

• snd_soc_set_runtime_hwparams(substream, &snd_imx_hardware);

  return 0;

-- 2.21.0