#define RING_BUFFER_GET_MMAP_READ_OFFSET _IOR(0xF6, 0x0B, unsigned long)
/* flush the current sub-buffer */
#define RING_BUFFER_FLUSH _IO(0xF6, 0x0C)
#define RING_BUFFER_GET_MMAP_READ_OFFSET _IOR(0xF6, 0x0B, unsigned long)
/* flush the current sub-buffer */
#define RING_BUFFER_FLUSH _IO(0xF6, 0x0C)