How to trouble-shooting "Can't get terminal parameters: Inappropriate ioctl for device" for LTE status setting

Purpose:

It lists Sierra EM7455 LTE troubleshooting  for customer reference, 

Target Audience:

For Advantech TSE, RBU AE, outsourcing service engineer(s) and End customer with the following knowledges  :

• Linux troubleshooting experience

Content:

IF Linux OS reports "Can't get terminal parameters: Inappropriate ioctl for device" after key-in "chat"  command.

This message means Linux OS not success to load "Qualcomm module" and initial Sierra LTE module. 

Example:

 # chat -V -s -t 2 '' 'at!uims? ' 'OK' '' > /dev/ttyUSB2 < /dev/ttyUSB2; echo

Can't get terminal parameters: Inappropriate ioctl for device

User needs to key-in following command to initial "Qualcomm module" 

# modprobe qcserial
# modprobe qmi_wwan

Please use  following command  to checks ttyUSB2 status, the dmesg message needs to report "Qualcomm USB modem converter now attached to ttyUSB2"

# dmesg | grep ttyUSB
[ 434.701538] usb 2-1: Qualcomm USB modem converter now attached to ttyUSB0
[ 434.703386] usb 2-1: Qualcomm USB modem converter now attached to ttyUSB1
[ 434.709123] usb 2-1: Qualcomm USB modem converter now attached to ttyUSB2

And using "lsusb -t" command checks "Driver=qcserial" status.,

# lsusb -t
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 5000M
    |__ Port 1: Dev 2, If 2, Class=Vendor Specific Class, Driver=qcserial, 5000M   
    |__ Port 1: Dev 2, If 0, Class=Vendor Specific Class, Driver=qcserial, 5000M
    |__ Port 1: Dev 2, If 3, Class=Vendor Specific Class, Driver=qcserial, 5000M
    |__ Port 1: Dev 2, If 8, Class=Vendor Specific Class, Driver=qmi_wwan, 5000M
    |__ Port 1: Dev 2, If 10, Class=Vendor Specific Class, Driver=qmi_wwan, 5000M
    |__ Port 3: Dev 3, If 0, Class=Mass Storage, Driver=usb-storage, 5000M
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 480M
    |__ Port 3: Dev 2, If 0, Class=Hub, Driver=hub/4p, 480M 

It can success to set/get sierra LTE module status by "chat" command after loading "Qualcomm module"

# chat -V -s -t 2 '' 'at!uims? ' 'OK' '' > /dev/ttyUSB2 < /dev/ttyUSB2; echo

at!uims?

!UIMS: 0

OK

When "lsusb -t" command doesn't show "Driver=qcserial" message, the LTE module seems to have something problem during loading qcserial module, kindly contact Advantech and send system to RMA. 

# lsusb -t
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 5000M
    |__ Port 1: Dev 2, If 13, Class=CDC Data, Driver=cdc_mbim, 5000M
    |__ Port 1: Dev 2, If 12, Class=Communications, Driver=cdc_mbim, 5000M
    |__ Port 3: Dev 3, If 0, Class=Mass Storage, Driver=usb-storage, 5000M
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 480M
    |__ Port 3: Dev 2, If 0, Class=Hub, Driver=hub/4p, 480M