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2nd USB CDC works at first, then device won't connect to computer #6018

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@Turtle49

Description

@Turtle49

CircuitPython version

Adafruit CircuitPython 7.1.1 on 2022-01-14; Adafruit Feather M4 Express with samd51j19
Adafruit CircuitPython 7.1.1 on 2022-01-14; Adafruit Feather M0 Adalogger with samd21g18 (2 different devices)

Code/REPL

#boot.py
import usb_cdc
usb_cdc.enable(console=True, data=True)    # Enable console and data

Behavior

When connected to a Windows machine sees the microcontroller as "Unknown USB device (device descriptor request failed)". When connected to a Rpi, there is no apparent acknowledgement of plugging it in and there are no new objects in /dev.

Description

I enabled CDC in boot.py as above and I established communications between microcontrollers (M4, 2 different M0 Adalogger) and hosts (3 different Win10 tested, Raspberry Pi 4). I wrote and successfully tested code, per Adafruit guides here, here and here (thank you!!).

A few hours later the device stops ceases to behave well. Instead, now when connected to a computer, the microcontroller is unable to connect to the computer in "normal" mode.

When connected to a Windows machine sees the microcontroller as "Unknown USB device (device descriptor request failed)" No new COM devices become present, REPL does not work, CIRCUITPY does not appear. I tried Device Cleanup Tool v1.2.1 to no avail. When connected to a Rpi, there is no apparent acknowledgement of plugging it in and there are no new objects in /dev (when it worked, I saw them as ttyACM0 and ttyACM1, rather than ttyUSBx).

However, the microcontrollers connect in "safe" and "boot" modes. Removing usb_cdc.enable from boot.py makes it so that REPL/CIRCUITPY connects as usual, and behaves as expected in other ways.

I have re-installed CircuitPython to no avail. I have not attempted previous versions (I can't navigate to the repository of my devices! please, link?). I have turned on, off, re-booted in various orders, and looked for newly-installed drivers.

Additional information

I wonder if it is related to issue #4986, in a way that makes the microcontroller unable to connect at all if the 2nd CDC is enabled.

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