On Wed, May 06, 2015 at 08:38:03PM +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 = 64 * 1024,

+};

As I said last time I'm not sure why you are manually defining these - the capabilities of the DMA controller should be being enumerated from the DMA controller driver. See dmaengine_pcm_set_runtime_hwparams().