Arch Linux

mxpl

Member

Registered: 2020-05-09

Posts: 3

USB Webcam: device descriptor read/64, error -71

** I previously posted this in the Newbie Corner but it didn't get any traction. Trying it here to see if it rings the bells of anyone here. **

My webcam stopped working about two weeks ago. I managed to have some time to take a look at it today.

Main symptom: it does not show up as input device in PulseAudio

This is the output of dmesg right after plugging the webcam.

[  499.521740] usb 1-1.6: new high-speed USB device number 16 using ehci-pci
[  499.941732] usb 1-1.6: device not accepting address 16, error -71
[  500.015069] usb 1-1.6: new high-speed USB device number 17 using ehci-pci
[  500.435078] usb 1-1.6: device not accepting address 17, error -71
[  500.435208] usb 1-1-port6: attempt power cycle
[  501.028400] usb 1-1.6: new high-speed USB device number 18 using ehci-pci
[  501.111750] usb 1-1.6: device descriptor read/64, error -71
[  501.301750] usb 1-1.6: device descriptor read/64, error -71
[  501.481734] usb 1-1.6: new high-speed USB device number 19 using ehci-pci
[  501.565068] usb 1-1.6: device descriptor read/64, error -71
[  501.755068] usb 1-1.6: device descriptor read/64, error -71
[  501.861823] usb 1-1-port6: unable to enumerate USB device

The error code seems to be related to a protocol error: https://github.com/torvalds/linux/blob/ … rrno.h#L54

It does not appear in lsusb:

Bus 004 Device 003: ID 046d:c077 Logitech, Inc. M105 Optical Mouse
Bus 004 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 004 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 046d:c31c Logitech, Inc. Keyboard K120
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub

I tried

echo Y | sudo tee /sys/module/usbcore/parameters/use_both_schemes

and

echo Y | sudo tee /sys/module/usbcore/parameters/old_scheme_first

alone and at the same time. It did not fix the problem.

I thought the problem was coming from the webcam but it works fine on a MacBook and a Windows Laptop.

I tried using different ports (both usb 3.0 and usb 2.0). I tried unplugging everything (incl. the power cord), waiting a few seconds and replugging everything.

Webcam model: Logitech c930e

I'm not using a usb hub.

Any idea where this could be coming from?

mxpl

Member

Registered: 2020-05-09

Posts: 3

Re: USB Webcam: device descriptor read/64, error -71

For posterity: the problem seems to be with this webcam. It started having weird flickering problems with it on my MacBook after a while. I think the hardware was slowly failing. I changed the webcam and I have no problems with it on my arch.

If you have these weird protocol-level errors, it probably means your USB device is broken.