On Thu, Apr 30, 2015 at 12:07:29PM +0800, Jun Nie wrote:

+static const struct snd_pcm_hardware snd_zx_hardware = {

• .info = SNDRV_PCM_INFO_MMAP |

• 		  SNDRV_PCM_INFO_MMAP_VALID |
  

• 		  SNDRV_PCM_INFO_INTERLEAVED |
  

• 		  SNDRV_PCM_INFO_PAUSE |
  

• 		  SNDRV_PCM_INFO_RESUME |
  

• 		  SNDRV_PCM_INFO_NO_PERIOD_WAKEUP,
  

• .period_bytes_min = 32,
• .period_bytes_max = 16 * 1024,
• .periods_min = 2,
• .periods_max = 32,
• .buffer_bytes_max = 60 * 1024,

+};

Can the generic DMA code not work this out by querying the dmaengine driver?

+int zx_pcm_platform_register(struct device *dev) +{

• return devm_snd_dmaengine_pcm_register(dev, &zx_dmaengine_pcm_config,

• 	SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME |
  

• 	SND_DMAENGINE_PCM_FLAG_NO_RESIDUE);
  

_NO_RESIDUE has been removed in current code, the core figures it out automatically. Like I said looking at the driver code I'm not clear why this is specifying _CUSTOM_CHANNEL_NAME either, it looked like the driver just used the one standard channel name.