I run embedded linux on a zedboard-like platform. I need to create udev rules for some various devices that will be plugged into it.
I have gadgetfs and configfs on in the kernel and I've built them as modules. If I load the modules I can then use an appropriate USB device with, like ethernet over usb to a laptop or something else.
The problem begins when I want to support hot plugging, and thus need to use udev rules. So I ran udevadm monitor but it doesn't show any kernel or udev triggers when any USB device is plugged in. If I load a module I can then see the kernel/udev triggers for the USB device as the module loads.
Is this normal behavior? I thought that the kernel should report that a USB is plugged in through a trigger, whether I had a module that could support it or not. Regular USB drivers are also built into the kernel but do not appear to work at all, which is why I moved onto using gadgetfs and configfs.
Does anyone know why my udev doesn't show trigger events without a gadget module loaded? I can't automate hot plugging if I can't see the trigger events when a USB is plugged in.
My USB controller is chipidea and I use it in OTG mode.