insmod: error inserting 'usb338x.ko': -1 Unknown symbol in module

Question

I compiled a driver then tried to load de module and this is the return

insmod: error inserting 'usb338x.ko': -1 Unknown symbol in module

and dmesg

[ 8128.506098] usb338x: Unknown symbol usb_add_gadget_udc (err 0)
[ 8128.506116] usb338x: Unknown symbol usb_gadget_unmap_request (err 0)
[ 8128.506127] usb338x: Unknown symbol usb_del_gadget_udc (err 0)
[ 8128.506138] usb338x: Unknown symbol usb_gadget_map_request (err 0)

Answer 1

reading other post i realized that i need to load the udc_core

modprobe udc_core

thats it!

Answer 2

Or you can try this : MODULE_LICENSE("GPL") add to your kernel module file.