USB HID Digitizer and CDC not working

Hello, is there any information on what HID devices are supported in the Android release? I am making a composite HID device but it appears that only certain devices are supported, even though they are enumerating. I tested each HID device individually and it appears that Digitizers (Pen and Touch) and CDC (serial communication) do not work. Mouse and Keyboard work well.

These devices all work on Linux, Mac and Windows.

Any help would be greatly appreciated! Thanks!

The first step is to check that everything is good at kernel level, is your device attached to a driver once enumerated ? if not you need to rebuild the kernel/modules with the corresponding driver enabled, if yes the device should create a new device in /dev/input/…

Could you provide dmesg output to see what happens when pluggin the device.

Thank you for the response! Yeah, thats what I was afraid of. The device is enumerating, so I just need to dig into the kernel/modules/drivers and then rebuild.