USB descriptor reads fail on RP2350 USB host with composite/dynamic devices (usb.core.USBError)

[i-am-me0-0]

CircuitPython version and board name

Adafruit CircuitPython 10.0.3 on 2025-10-17; Raspberry Pi Pico 2 with rp2350a

Raspberry Pi Pico 2 - https://www.waveshare.com/wiki/RP2350-USB-A

Code/REPL

import usb_host
import board

usb_host.Port(board.GP12, board.GP13)


# SPDX-License-Identifier: Unlicense

import usb.core


from relic_usb_host_descriptor_parser import DeviceDescriptor


for i, device in enumerate(usb.core.find(find_all=True)):

    device_descriptor = DeviceDescriptor(device)

    print(f"Device {i+1}: {device_descriptor}")

    for j, configuration in enumerate(device_descriptor.configurations):

        print(f"- Configuration {j+1}: {configuration}")

        for k, interface in enumerate(configuration.interfaces):

            print(f"  - Interface {k+1}: {interface}")

            for l, endpoint in enumerate(interface.endpoints):

                print(f"    - Endpoints {l+1}: {endpoint}")

    print()

Behavior

Traceback (most recent call last):
  File "<stdin>", line 17, in <module>
  File "relic_usb_host_descriptor_parser.py", line 285, in __init__
  File "adafruit_usb_host_descriptors.py", line 87, in get_device_descriptor
  File "adafruit_usb_host_descriptors.py", line 75, in get_descriptor
usb.core.USBError: 

that is the error message and is is related to descriptors specifically, this code does work which is only the PID and VID

import usb_host
import board

usb_host.Port(board.GP12, board.GP13)
import usb.core

for device in usb.core.find(find_all=True):
    print(device.idVendor, device.idProduct)

which results in
1118 654
in repl

Description

On RP2350-based boards acting as a USB host, attempting to read USB device descriptors using usb.core raises usb.core.USBError for certain devices that enumerate dynamically or expose multiple interfaces (e.g. 8BitDo USB Wireless Adapter 2).

Additional information

I have done a bunch of testing and debugging
Most importantly it seems to always come back to an error in the adafruit_usb_host_descriptors.py library

Further in the adafruit discord (help-with-circuitpython) there is an entire conversation history of everything I have tried and suggestions of others
I feel that is too large to add here but any questions i will answer.

Also this is my first time writing a GitHub issue, how did i do?

[RetiredWizard]

Can you try a test using a slightly modified version of Adafruit's Host descriptor library and this code snippet?

You'll need to rename any copies of adafruit_usb_host_descriptors.mpy you have in the /lib folder or the root folder of your device and then copy the adafruit_usb_host_descriptors.py from here (use the "download raw file" icon near the top of the code) to the /lib folder on your device. Once you have the .py file there on line 152 change USAGE_MOUSE to USAGE_GAMEPAD.

import usb.core
import adafruit_usb_host_descriptors
from traceback import print_exception

for device in usb.core.find(find_all=True):
# print device info
	try:
	    try:
		print(f"{device.idVendor:04x}:{device.idProduct:04x}")
	    except usb.core.USBError as e:
		print_exception(e, e, None)
	    try:
		print(device.manufacturer, device.product)
	    except usb.core.USBError as e:
		print_exception(e, e, None)
	    print()
	    config_descriptor = adafruit_usb_host_descriptors.get_configuration_descriptor(
		device, 0
	    )
	    print(config_descriptor)

	    _possible_interface_index, _possible_endpoint_address = adafruit_usb_host_descriptors.find_report_mouse_endpoint(device)
	    if _possible_interface_index is not None and _possible_endpoint_address is not None:
		mouse_device = device
		mouse_interface_index = _possible_interface_index
		mouse_endpoint_address = _possible_endpoint_address
		print(
		    f"gamepad interface: {mouse_interface_index} "
		    + f"endpoint_address: {hex(mouse_endpoint_address)}"
		)
		break
	    print(f"was not a {deviceType} gamepad")
	except usb.core.USBError as e:
	    print_exception(e, e, None)

EDIT: added missing import....

[i-am-me0-0]

I have done that
and i get

2dc8:3106
Traceback (most recent call last):
  File "<stdin>", line 49, in <module>
usb.core.USBError: 

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 51, in <module>
NameError: name 'print_exception' isn't defined

line 49 being
print(device.manufacturer, device.product)

this is the same with just the dongle no controller connected or dongle with controller connected

[RetiredWizard]

My bad, you need to add from traceback import print_exception near the top of the code snippet.... Sorry :/

[i-am-me0-0]

happens :)

2dc8:3106
usb.core.USBError: 

usb.core.USBError: 

not much more to be honest....

[RetiredWizard]

weird, the two errors sort of make sense but the snippet should have printed either the found interface or the "was not a gamepad" message (github isn't displaying the indention right but when I copy the code it seems okay)

[RetiredWizard]

Maybe I'm hiding too much info, can you try again with this snippet, this one let's it crash on the get_configuration call:

import usb.core
import adafruit_usb_host_descriptors
from traceback import print_exception

for device in usb.core.find(find_all=True):
# print device info
    try:
	print(f"{device.idVendor:04x}:{device.idProduct:04x}")
    except usb.core.USBError as e:
	print_exception(e, e, None)
    try:
	print(device.manufacturer, device.product)
    except usb.core.USBError as e:
	print_exception(e, e, None)
    print()
    config_descriptor = adafruit_usb_host_descriptors.get_configuration_descriptor(
	device, 0
    )
    print(config_descriptor)

    _possible_interface_index, _possible_endpoint_address = adafruit_usb_host_descriptors.find_report_mouse_endpoint(device)
    if _possible_interface_index is not None and _possible_endpoint_address is not None:
	mouse_device = device
	mouse_interface_index = _possible_interface_index
	mouse_endpoint_address = _possible_endpoint_address
	print(
	    f"gamepad interface: {mouse_interface_index} "
	    + f"endpoint_address: {hex(mouse_endpoint_address)}"
	)
	break
    print(f"was not a {deviceType} gamepad")

[i-am-me0-0]

2dc8:3106
usb.core.USBError: 

Traceback (most recent call last):
  File "<stdin>", line 53, in <module>
  File "/lib/adafruit_usb_host_descriptors.py", line 98, in get_configuration_descriptor
  File "/lib/adafruit_usb_host_descriptors.py", line 75, in get_descriptor
usb.core.USBError: 

this part fails
config_descriptor = adafruit_usb_host_descriptors.get_configuration_descriptor(
device, 0
)

[RetiredWizard]

Okay, that's a core call:

device.ctrl_transfer(
        _REQ_RCPT_DEVICE | _REQ_TYPE_STANDARD | _DIR_IN,
        _REQ_GET_DESCRIPTOR,
        wValue,
        wIndex,
        buf,
    )

I don't have any hardware that reproduces the issue but that points to a place to start looking....