Error EPROTO (-71) with Intel 8265 Bluetooth module


We have a custom board carrier board where we directly connected the USB pins on the Intel 8265 module (for Bluetooth) to the USB2 pins on the Jetson Nano, without a USB hub.

Sometimes (not all the time), we will see that the Bluetooth is not enumerated over USB. We added some extra debugging in the xhci_hcd driver to understand the error when the device fails to enumerate.

The kernel log is attached.

Can you provide any insight?

Thank you,dmesg_bt_not_working_20210120.txt (71.8 KB)

If this issue only happens to custom board, maybe you should do the tuning for SI.


We checked the reference design that Nvidia provides and it matches our custom carrier board with respect to USB2.0 (the hub is only used for USB3.0). We’ve also confirmed that the lines from the USB2_ module going to the Intel Bluetooth module are impedance matched. We also have the USB1 lines come out to a USB Type-A port. When we’re having issues with the Bluetooth module, the USB flash drive also fails to enumerate. Is there a way that we can reset just the USB subsystem?