USB gadget API framework with gadgetfs
 

I am using the USB gadget API framework with gadgetfs together with the example \
usermode driver usb.c. My target platform is an \
i.MX31 ARM11 with a arc_udc controller driver. The example usermode driver was \
modified to be started as a thread, it is NOT the original standalone driver. The \
normal execution of the usermode driver works fine, but for us it is necessary to \
terminate and restart usb-endpoint-pthreads (source, sink, ep0) because we need to \
disconnect USB during application runtime. In some cases arc_udc isn't able to unload \
gadgetfs("Device or resource busy"). The sticking point from my point of view is \
terminating endpoint0. Has anyone got similar constellation/problems/experience?
Can someone point me in the right direction to avoid the "Device or resource busy" \
error? Is there a way of querying the state (busy/free) of the gadgetfs from \
usermode?

Thanks in advance.