#define MAXPACK 50
  #define MAXBUFFERMS 100
  #define MAXSTRIDE 3
  
  #define SSS (((MAXPACK*MAXBUFFERMS*MAXSTRIDE + 4096) / 4096) * 4096)
  struct snd_usX2Y_hwdep_pcm_shm {
  	char playback[SSS];
  	char capture0x8[SSS];
  	char capture0xA[SSS];
  	volatile int playback_iso_head;
  	int playback_iso_start;
  	struct {
  		int	frame,
  			offset,
  			length;
  	} captured_iso[128];
  	volatile int captured_iso_head;
  	volatile unsigned captured_iso_frames;
  	int capture_iso_start;
  };

  
  int usX2Y_hwdep_pcm_new(struct snd_card *card);