[USB] Could not claim interface  on USB device: -6

1

Hi,
I have a problem with python multiprocessing and odrive.
My parent process uses 2 odrive:
odrv0 = odrive.find_any(serial_number = “2073399A4D4D”)
odrv1 = odrive.find_any(serial_number = “208339864D4D”)

My child process need to access the odrives so I execute another time:
odrv0 = odrive.find_any(serial_number = “2073399A4D4D”)
odrv1 = odrive.find_any(serial_number = “208339864D4D”)

It was working well with firmware 0.51.
I just upgraded to firmware 0.54 and I get this error when I spawn the child process:
13:48:40.581106970 [USB] Could not claim interface on USB device: -6
13:48:40.581647970 [USB] Could not claim interface on USB device: -6

Could you please help me fixing that error or finding a workaround?

I already tried to pass odrv0 and odrv1 in multiprocess queue, but it doesn’t work.
I already checked support on github and found that it is supposed to be fixed: rewrite find_any() to support multiple calls · odriverobotics/ODrive@6a9bc83 · GitHub

thank you for your help.
Fabien

2

Accessing ODrives from multiple processes is currently unfortunately not supported. I’m not too familiar with Python’s multiprocessing but maybe you can reorganize your code so that the ODrive I/O is all in one process.

1 Like
3

Hi Samuel,
Thank you for your answer.
Do you plan to add this python multiprocess functionality in a near future?

Redeclaring odrive in different processes was working ok in fw 0.51dev.
Do you know why?