在測試alsa driver時,用aplay播一個wav 音樂
但只播放到前一小段聲音而已,大概只有幾K吧
後來就一直重覆那一小段,aplay有出現underrun訊息
是不是buffer_bytes_max,buffer_bytes_max要修改呢
還是可能哪個部份出問題了

static struct snd_pcm_hardware snd_nxc2600_hw =
{
   .info                        = (SNDRV_PCM_INFO_INTERLEAVED | 
         SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID),                            .formats                = SNDRV_PCM_FMTBIT_S16_LE,
   .rates                  = (SNDRV_PCM_RATE_48000),
   //.rate_min               = 48000,
   .rate_min               = 8000,                                                    .rate_max                    = 48000,
   .channels_min                = 1,
   .channels_max                = 2,
   //.buffer_bytes_max       = 128*1024,                                              .buffer_bytes_max       = 32*1024,
   //.period_bytes_min       = 32,                                                    .period_bytes_min       = 4*1024,
   .period_bytes_max       = 32*1024,
   .periods_min            = 2,
   .periods_max            = 4,
   .fifo_size              = 16,
};

双缓冲结构，貌似你填充数据太慢了，导致dma产生underun，是吧