Dear Community,
we have a Raspberry Pi Compute Module 3+ setup with 2 USB connections required. The Raspberry Pi itself offers only 1 USB Port, so we are using the TUSB2036 (USB 2.0 12M) hub.
Connected to the TUSB2036 are:
- At downstream port 1: A LTE modem, which is on the same board, configured to be permanent
- At downstream port 2: An externally available USB port with overcurrent protection and external passive components as suggested in the datasheet, configured to be removable
- At downstream port 3: Left unconnected and is disabled
The LTE modem works fine, but there is a problem with the externally available USB port. Whenever a HID (Keyboard, Mouse) is connected, the OS (Raspbian Minimum) does not recognize the device. The only thing happening is a power cycle on the USB port (PWRON high-low cycle), which is also reported when calling dmesg. However, when connecting a device different from a HID (USB flash drive, WiFi dongle, Smartphone, ...), everything works as expected. The same thing happens even if another powered USB hub is placed in between the TUSB2036 and the external devices. We could not get any HID to work, and we could net get any other device to not work.
Is there a known problem in a linux driver or in the hub that may cause this?
Kind regards
Christian
