#define SNDRV_PCM_TRIGGER_PAUSE_RELEASE        4
 #define SNDRV_PCM_TRIGGER_SUSPEND      5
 #define SNDRV_PCM_TRIGGER_RESUME       6
+#define SNDRV_PCM_TRIGGER_DRAIN                7
 
 #define SNDRV_PCM_POS_XRUN             ((snd_pcm_uframes_t)-1)
 
 
 #define SNDRV_PCM_INFO_SYNC_START      0x00400000      /* pcm support some kind of sync go */
 #define SNDRV_PCM_INFO_NO_PERIOD_WAKEUP        0x00800000      /* period wakeup can be disabled */
 #define SNDRV_PCM_INFO_HAS_WALL_CLOCK   0x01000000      /* has audio wall clock for audio/system time sync */
+#define SNDRV_PCM_INFO_DRAIN_TRIGGER   0x40000000              /* internal kernel flag - trigger in drain */
 #define SNDRV_PCM_INFO_FIFO_IN_FRAMES  0x80000000      /* internal kernel flag - FIFO size is in frames */
 
 typedef int __bitwise snd_pcm_state_t;
 
 
        hw = &substream->runtime->hw;
        if (!params->info) {
-               params->info = hw->info & ~SNDRV_PCM_INFO_FIFO_IN_FRAMES;
+               params->info = hw->info & ~(SNDRV_PCM_INFO_FIFO_IN_FRAMES |
+                                           SNDRV_PCM_INFO_DRAIN_TRIGGER);
                if (!hw_support_mmap(substream))
                        params->info &= ~(SNDRV_PCM_INFO_MMAP |
                                          SNDRV_PCM_INFO_MMAP_VALID);
                        snd_pcm_post_stop(substream, new_state);
                }
        }
+
+       if (runtime->status->state == SNDRV_PCM_STATE_DRAINING &&
+           runtime->trigger_master == substream &&
+           (runtime->hw.info & SNDRV_PCM_INFO_DRAIN_TRIGGER))
+               return substream->ops->trigger(substream,
+                                              SNDRV_PCM_TRIGGER_DRAIN);
+
        return 0;
 }