UVC ioctl call is failing

Hi All, I have iCatch camera connected to my ubuntu 16.04 desktop, I'm trying to use GET_CUR and SET_CUR commands to control the camera Extension Unit. I have a common api for both get and set which first queries the camera with get_len and then send get or set command. But When I call a set or get command repeatedly without any delay, the ioctl is failing due to timeout, If I set UVC_CTRL_CONTROL_TIMEOUT to 0 (infinite) or more or delay between (min 2 sec ) get and set commands It will complete successfully. But same thing is working when I tried in windows. Is delay required between repeated ioctl calls? If so, why? Thank you, manoj