Can't get camera control parameter. GET INFO error

Hello everyone, Recently, I am trying developing the gadget uvc function, I can get the video streaming normal. When I want to control the camera parameter such as zoom and focus. I happened some troubles. I use AMCAP　software and when I open the attribute and camera control menus, I find all of the controls is not use. Shown as the below image :

I use bushound to catch the data and I find when the host send get info command and the gadget does not respond. I don't know why. Does anyone have happend the same issue?