Connect Sierra Wireless AirPrime MC7455 to IMX 8

Dear community,
I have a problem connecting my lte modem to the imx8. So far I saw in [https://developer.toradex.com/peripheral-devices/airprime-mc7455], that the modem I am using has been tested for the imx6.
I followed this instruction [https://developer.toradex.com/knowledge-base/modem-support] to use 4g on my imx8. The ModemManager (mmcli) was not able to find any modem. Also with the lsusb command I could not find an added device. I checked dmesg but could not find anything that would indicate a device, connected over the pcie interface. The dmesg output with and without modem, just like the modemmanager debug outputs are here. I connected another module to the pcie port, that one was visable in dmesg, though mmcli couldn’t detect any connected modem again.

Thanks for the replies.

Greetings @harun_iis!

This device should connect over the USB lines present on the mini PCIe interface.
We’ve just tried this with the Apalis iMX8QM 4GB WB IT V1.1B and an Ixora V1.1A to see that the device is indeed enumerated on the USB bus:

apalis-imx8-06804751:~$ lsusb
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 003: ID 1199:68c0 Sierra Wireless, Inc. 
Bus 003 Device 004: ID 1286:204e Marvell Semiconductor, Inc. 
Bus 003 Device 002: ID 0424:3503 Microchip Technology, Inc. (formerly SMSC) 
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

And the dmesg log:

apalis-imx8-06804751:~$ dmesg | grep usb
[    0.138719] usbcore: registered new interface driver usbfs
[    0.138750] usbcore: registered new interface driver hub
[    0.138814] usbcore: registered new device driver usb
[    1.597409] cdns-usb3 5b110000.usb3: Adding to iommu group 2
[    1.600154] usbcore: registered new interface driver usb-storage
[    1.600227] usbcore: registered new interface driver usbserial_generic
[    1.600245] usbserial: USB Serial support registered for generic
[    1.703473] usbcore: registered new interface driver usbhid
[    1.703476] usbhid: USB HID core driver
[    1.739984] usbcore: registered new interface driver snd-usb-audio
[    1.876477] mxs_phy 5b100000.usbphy: 5b100000.usbphy supply phy-3p0 not found, using dummy regulator
[    1.890481] usb_phy_generic bus@5b000000:usb3-phy: bus@5b000000:usb3-phy supply vcc not found, using dummy regulator
[    1.890638] usb_phy_generic bus@5b000000:usbphynop2: bus@5b000000:usbphynop2 supply vcc not found, using dummy regulator
[    1.932651] usb3503 3-0008: switched to HUB mode
[    1.932662] usb3503 3-0008: usb3503_probe: probed in hub mode
[    2.008003] usb usb2: We don't know the algorithms for LPM for this host, disabling LPM.
[    2.010139] imx_usb 5b0d0000.usb: 5b0d0000.usb supply vbus not found, using dummy regulator
[    2.611263] usb 3-1: new high-speed USB device number 2 using ci_hdrc
[    6.674119] usb 3-1.2: new high-speed USB device number 3 using ci_hdrc
[    6.822129] usb 3-1.2: config 1 has an invalid interface number: 8 but max is 5
[    6.822141] usb 3-1.2: config 1 has an invalid interface number: 10 but max is 5
[    6.822146] usb 3-1.2: config 1 has an invalid interface number: 11 but max is 5
[    6.822151] usb 3-1.2: config 1 has no interface number 1
[    6.822155] usb 3-1.2: config 1 has no interface number 4
[    6.822159] usb 3-1.2: config 1 has no interface number 5
[    7.536100] usbcore: registered new interface driver qcserial
[    7.536328] usbserial: USB Serial support registered for Qualcomm USB modem
[    7.537920] usb 3-1.2: Qualcomm USB modem converter now attached to ttyUSB0
[    7.538790] usb 3-1.2: Qualcomm USB modem converter now attached to ttyUSB1
[    7.539497] usb 3-1.2: Qualcomm USB modem converter now attached to ttyUSB2
[    7.542771] usbcore: registered new interface driver cdc_wdm
[    7.550557] qmi_wwan 3-1.2:1.8 wwan0: register 'qmi_wwan' at usb-ci_hdrc.1-1.2, WWAN/QMI device, 82:d7:41:5a:1f:58
[    7.552444] qmi_wwan 3-1.2:1.10 wwan1: register 'qmi_wwan' at usb-ci_hdrc.1-1.2, WWAN/QMI device, 82:d7:41:5a:1f:58
[    7.552600] usbcore: registered new interface driver qmi_wwan
[    9.521341] usb 3-1.1: new high-speed USB device number 4 using ci_hdrc
[    9.709077] usbcore: registered new interface driver btusb

Can you please retry this with 1) the latest TorizonCore nightly 2) the latest TorizonCore monthly available?

I did and it did not work out unfortunately. There is this message in the booting process I wanted to share:
logs

Hi,
I had same problem, I fix it covering,( disconnecting) pin 23 of the modem from the pcei connector.

You my friend are the man! Thank you that was the solution for me. Do you know what was the reason behind this?

@harun_iis,

Pin 23 appears to be connected to the PCIE_RXN signal. It could be that something - a driver or a device tree configuration - is driving that pin somehow and for some reason it doesn’t let the device work over USB.

I’ve seen reports of such issues in other forums, so I would guess this is on Sierra’s side and what’s running on the modem, but could also be a Linux driver issue.