ncDeviceOpen problems

mattdibi

Hi,
I successfully installed the NCSDK in API-only mode on a custom platform (x86-64) and ran the examples. However, from time to time, I get the following errors upon opening the connection with the device:

W: [         0] ncDeviceOpen:533    failed to find device

ncDeviceOpen Failed [-2]: Could not open the device.

and

E: [         0] dispatcherEventSend:730 Write failed -4

Hello NCS! Device opened normally.
Goodbye NCS!  Device Closed normally.
NCS device working.

Log of a successful run (dmesg):

[Sep19 07:29] usb 3-1: USB disconnect, device number 2
[  +0.248874] usb 4-1: new SuperSpeed USB device number 2 using xhci_hcd
[  +0.020071] usb 4-1: New USB device found, idVendor=03e7, idProduct=f63b
[  +0.006850] usb 4-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  +0.008001] usb 4-1: Product: VSC Loopback Device
[  +0.005103] usb 4-1: Manufacturer: Intel Corporation
[  +0.005347] usb 4-1: SerialNumber: 1FF861D5542010
[  +1.242801] usb 3-1: new high-speed USB device number 3 using xhci_hcd
[  +0.134026] usb 3-1: New USB device found, idVendor=03e7, idProduct=2150
[  +0.006821] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  +0.007819] usb 3-1: Product: Movidius MA2X5X
[  +0.004701] usb 3-1: Manufacturer: Movidius Ltd.
[  +0.004939] usb 3-1: SerialNumber: 03e72150
[  +0.351915] xhci_hcd 0000:02:00.0: Cannot set link state.
[  +0.007609] usb usb4-port1: cannot disable (err = -32)
[  +0.005258] usb 4-1: USB disconnect, device number 2

Log of a unsuccessful run:

[  +0.250331] usb 4-1: new SuperSpeed USB device number 33 using xhci_hcd
[  +0.019707] usb 4-1: New USB device found, idVendor=03e7, idProduct=f63b
[  +0.006873] usb 4-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  +0.007885] usb 4-1: Product: VSC Loopback Device
[  +0.005087] usb 4-1: Manufacturer: Intel Corporation
[  +0.005335] usb 4-1: SerialNumber: 1FF861D5542010

It seems like when switching from USB2.0 to USB3.0 it gets stuck.
This happens both using the hello_ncs_cpp example and the python examples from the ncappzoo. After a few tries the examples start, other times (more commonly) the examples starts right away.

Notes:

• This problem emerged using both the Movidius Neural Compute Stick and the UP AI Core.
• The USB connection is provided by an internal USB hub.

What could be the possible cause of this behaviour?

mattdibi

For future reference: I uninstalled the ncsdk 2.05.00.02 and installed the 1.12.00.01. Now everything works correctly.