V4L2_CTRL_CLASS_USER 68 include/uapi/linux/v4l2-controls.h #define V4L2_CID_BASE (V4L2_CTRL_CLASS_USER | 0x900) V4L2_CTRL_CLASS_USER 70 include/uapi/linux/v4l2-controls.h #define V4L2_CID_USER_CLASS (V4L2_CTRL_CLASS_USER | 1)