BG96 enumerating on different serial ports

IoT Modules LPWA Module
1

We had a system (BG96 modem connected to i.MX6UL host processor via USB – running Linux) that would not connect for 3 days, and after it connected we looked at the logs and discovered the modem was enumerating on the wrong ports:

Jun 23 10:54:22 imx6ul-var-dart kern.info kernel: usb 2-1: new high-speed USB device number 9 using ci_hdrc
Jun 23 10:54:22 imx6ul-var-dart kern.info kernel: option 2-1:1.0: GSM modem (1-port) converter detected
Jun 23 10:54:22 imx6ul-var-dart kern.info kernel: usb 2-1: GSM modem (1-port) converter now attached to ttyUSB0
Jun 23 10:54:22 imx6ul-var-dart kern.info kernel: option 2-1:1.1: GSM modem (1-port) converter detected
Jun 23 10:54:22 imx6ul-var-dart kern.info kernel: usb 2-1: GSM modem (1-port) converter now attached to ttyUSB1
Jun 23 10:54:22 imx6ul-var-dart kern.info kernel: option 2-1:1.2: GSM modem (1-port) converter detected
Jun 23 10:54:22 imx6ul-var-dart kern.info kernel: usb 2-1: GSM modem (1-port) converter now attached to ttyUSB4
Jun 23 10:54:23 imx6ul-var-dart kern.info kernel: option 2-1:1.3: GSM modem (1-port) converter detected   
Jun 23 10:54:23 imx6ul-var-dart kern.info kernel: usb 2-1: GSM modem (1-port) converter now attached to ttyUSB5
Jun 23 10:54:23 imx6ul-var-dart kern.info kernel: qmi_wwan 2-1:1.4: cdc-wdm0: USB WDM device

It should look like:

Jun 23 11:47:39 imx6ul-var-dart kern.info kernel: usb 2-1: GSM modem (1-port) converter now attached to ttyUSB0
Jun 23 11:47:39 imx6ul-var-dart kern.info kernel: option 2-1:1.1: GSM modem (1-port) converter detected
Jun 23 11:47:39 imx6ul-var-dart kern.info kernel: usb 2-1: GSM modem (1-port) converter now attached to ttyUSB1
Jun 23 11:47:39 imx6ul-var-dart kern.info kernel: option 2-1:1.2: GSM modem (1-port) converter detected
Jun 23 11:47:39 imx6ul-var-dart kern.info kernel: usb 2-1: GSM modem (1-port) converter now attached to ttyUSB2
Jun 23 11:47:39 imx6ul-var-dart kern.info kernel: option 2-1:1.3: GSM modem (1-port) converter detected
Jun 23 11:47:39 imx6ul-var-dart kern.info kernel: usb 2-1: GSM modem (1-port) converter now attached to ttyUSB3

If we can’t establish a connection, we reset the modem a number of times and then after 20m, the system reboots, so this unit was rebooting for 3 days and continuously enumerating on ports /dev/ttyUSB0/1/4/5 instead of /dev/ttyUSB0/1/2/3. We’ve not seen this before, so it seems like a pretty rare problem.

Does anyone have any ideas why this might be happening?

Thanks!

2

Hello

The index of USB enumberate is managed by host, BG96 USB list /dev/ttyUSB0/1/4/5 is usually due to ttyUSB2/3 is locked or file is still exsit by some error. You would need to manually delete revelant ttyUSB2/3 files then reboot device.

Best Regards,

3

we have also facing similiar issue
@cbrake have you resolved this issue?