CONFIG_USB_GADGET_DUALSPEED (not configurable)

configname: CONFIG_USB_GADGET_DUALSPEED

Linux Kernel Configuration
└─>Device Drivers
└─>USB support
└─>USB Gadget Support
└─>USB_GADGET_DUALSPEED
In linux kernel since version 2.6.20 (release Date: 2007-02-04)  
Means that gadget drivers should include extra descriptors
and code to handle dual-speed controllers.