On Fri, Mar 05, 2021 at 01:09:16PM +0100, Sedat Dilek wrote:

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

quoted

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?

Don't worry about trying to decode the output.  To me it looks like the 
drive crashes and needs to be reset at times when the computer sends it 
an ATA command.  (Not all ATA commands, but some.)  You can prevent this 
by setting the following module parameter for the usb-storage driver:

	quirks=174c:55aa:t

where the two numbers are the Vendor and Product IDs for the external 
drive, and the 't' is a quirks flag saying not to use any ATA commands.  
If this module parameter fixes the problem, we can add a permanent quirk 
setting to the kernel.

Alan Stern