On Mon, Mar 1, 2021 at 4:53 PM Alan Stern [off-list ref] wrote:
[ ... ]

You can use usbmon on bus 4 to record the USB traffic.  It may indicate
why the resets occur.

Hi Alan,

I followed the instructions in [1].

root# modprobe -v usbmon

root# ls /sys/kernel/debug/usb/usbmon
0s  0u  1s  1t  1u  2s  2t  2u  3s  3t  3u  4s  4t  4u

root# cat /sys/kernel/debug/usb/usbmon/4u > /tmp/usbmon-log_4u.txt
[ Ctrl+C ]

I recorded 13:03 - 13:04 (one minute).

So these xhci-resets should be included:

[Fri Mar  5 13:03:07 2021] usb 4-1: reset SuperSpeed Gen 1 USB device
number 2 using xhci_hcd
[Fri Mar  5 13:03:07 2021] usb 4-1: reset SuperSpeed Gen 1 USB device
number 2 using xhci_hcd
[Fri Mar  5 13:03:27 2021] usb 4-1: reset SuperSpeed Gen 1 USB device
number 2 using xhci_hcd
[Fri Mar  5 13:03:27 2021] usb 4-1: reset SuperSpeed Gen 1 USB device
number 2 using xhci_hcd
[Fri Mar  5 13:03:27 2021] usb 4-1: reset SuperSpeed Gen 1 USB device
number 2 using xhci_hcd
[Fri Mar  5 13:03:28 2021] usb 4-1: reset SuperSpeed Gen 1 USB device
number 2 using xhci_hcd
[Fri Mar  5 13:03:28 2021] usb 4-1: reset SuperSpeed Gen 1 USB device
number 2 using xhci_hcd

The usbmon-log is attached.

Unsure how to interpret the log - the kernel-doc says `raw data`.
How can I bring this into a human-readable format?
Can you give me a hand?

Regards,
- Sedat -

[1] https://www.kernel.org/doc/Documentation/usb/usbmon.