On Mon, Sep 3, 2018 at 3:40 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > On Mon, Sep 03, 2018 at 09:39:14AM +0300, Ranran wrote: > > Hello, > > > > I try to add gadget configfs as described in: > > https://www.kernel.org/doc/Documentation/usb/gadget_configfs.txt > > Yet, I find nothing in /sys/class/udc: > > > > user@user-VirtualBox:~/tegra$ ls /sys/class/udc/ -al > > total 0 > > drwxr-xr-x 2 root root 0 Sep 3 00:30 . > > drwxr-xr-x 58 root root 0 Sep 3 00:30 .. > > > > I also don't have dwc2, but dwc3: > > user@user-VirtualBox:~/tegra$ lsmod | grep dw > > dwc3 90112 0 > > ulpi 16384 1 dwc3 > > udc_core 24576 2 dwc3,libcomposite > > user@user-VirtualBox:~/tegra$ > > > > Kernel is 4.4.50. > > Why do you think the dwc3 driver will work here? Do you really have > this hardware being emulated? > Hi, I check it with Intel's E3900. In datasheet, I can't find it being described in details in datasheet, yet being linked with another document ("see Section Little-Endian and Big-Endian in the DWC SuperSpeed USB 3.0 Controller User Guide" ) https://www.mouser.com/ds/2/612/atom-e3800-family-datasheet-915661.pdf I have installed module dwc3 and also dwc2 (both compiled as modules), but nothing appear in /sys/class/udc I also tried to add all options in device-drivers->usb->usb gadget->usb peripheral control into kernel, (not as modules, but built into kernel). Yet, on checking ls /sys/class/udc I only find dummy_udc.0 , and nothing else. Thank you for any idea, ranran > And 4.4.50 is very old, please use a modern kernel please. > > thanks, > > greg k-h