Sierra Wireless EM7455 Modem stopped working

pynting · 12-13-2022, 04:20 AM

Hi,
The LTE module in my laptop suddenly stopped working. It has been working well right out of the box since I got the laptop several years ago and needed no additional driver, but now it suddenly is no longer initialized.

Distro:
Fedora 36 Workstation 64-bit

Modem:
$ lsusb
Bus 001 Device 014: ID 1199:9078 Sierra Wireless, Inc. Sierra Wireless EM7455 Qualcomm

I have tried to switch to an earlier kernel in grub to see if it happened after a kernel upgrade, but it did not make any difference, in addition, I could see that it stopped working in-between dnf updates.

By looking first at the dmesg output, and then compare that to an earlier log from before it stopped working, it seems to be some issue with qcserial trying to handle the device, and previously it was cdc-mbim? I do not know what changed, but qcserial was not mentioned in the logs much before, and after it broke, cdc-mbim is no longer mentioned much. After qcserial took over, it is no longer mentioned as a network device when running ifconfig. Another change is that it now is listed as a serial device (this was not the case when it was working), but trying to connect to it via some terminal fails.

Here is some more info that might help to diagnose the problem:

Code:

$ cat /lib/udev/rules.d/* | grep 9078
$ cat /lib/udev/rules.d/* | grep 1199
ATTR{idVendor}=="1199", ATTR{idProduct}=="0fff", RUN+="usb_modeswitch '/%k'"
ATTR{idVendor}=="1199", ATTR{idProduct}=="9011", RUN+="usb_modeswitch '/%k'"
ATTR{idVendor}=="1199", ATTR{idProduct}=="9013", RUN+="usb_modeswitch '/%k'"
ATTR{idVendor}=="1199", ATTR{idProduct}=="9017", RUN+="usb_modeswitch '/%k'"
ATTR{idVendor}=="1199", ATTR{idProduct}=="901b", RUN+="usb_modeswitch '/%k'"
ATTR{idVendor}=="1199", ATTR{idProduct}=="901c", RUN+="usb_modeswitch '/%k'"
ATTR{idVendor}=="1199", ATTR{idProduct}=="901f", RUN+="usb_modeswitch '/%k'"
ATTR{idVendor}=="1199", ATTR{idProduct}=="9041", RUN+="usb_modeswitch '/%k'"
ATTR{idVendor}=="1199", ATTR{idProduct}=="9051", RUN+="usb_modeswitch '/%k'"
ATTR{idVendor}=="1199", ATTR{idProduct}=="9053", RUN+="usb_modeswitch '/%k'"
ATTR{idVendor}=="1199", ATTR{idProduct}=="9063", RUN+="usb_modeswitch '/%k'"
SUBSYSTEMS=="usb", ATTRS{idVendor}=="1199", GOTO="mm_sierra"
ATTRS{idVendor}=="1199", ATTRS{idProduct}=="9057", ENV{ID_MM_QMI_CONNECTION_STATUS_POLLING_ENABLE}="1"
ATTRS{idVendor}=="1199", ATTRS{idProduct}=="a001", ENV{ID_MM_PREFERRED_NETWORKS_CPOL_DISABLED}="1"
ATTRS{idVendor}=="1199", ATTRS{idProduct}=="9071", ENV{.MM_USBIFNUM}=="03", SUBSYSTEM=="tty", ENV{ID_MM_PORT_TYPE_AT_PRIMARY}="1"
ATTRS{idVendor}=="1199", ATTRS{idProduct}=="9071", ENV{.MM_USBIFNUM}=="02", SUBSYSTEM=="tty", ENV{ID_MM_PORT_TYPE_GPS}="1"
ATTRS{idVendor}=="1199", ATTRS{idProduct}=="9071", ENV{.MM_USBIFNUM}=="00", SUBSYSTEM=="tty", ENV{ID_MM_PORT_TYPE_QCDM}="1"
ATTRS{idVendor}=="1199", ATTRS{idProduct}=="9091", ENV{.MM_USBIFNUM}=="03", SUBSYSTEM=="tty", ENV{ID_MM_PORT_TYPE_AT_PRIMARY}="1"
ATTRS{idVendor}=="1199", ATTRS{idProduct}=="9091", ENV{.MM_USBIFNUM}=="02", SUBSYSTEM=="tty", ENV{ID_MM_PORT_TYPE_GPS}="1"
ATTRS{idVendor}=="1199", ATTRS{idProduct}=="9091", ENV{.MM_USBIFNUM}=="00", SUBSYSTEM=="tty", ENV{ID_MM_PORT_TYPE_QCDM}="1"

Logs when it was working:

Code:

Nov 15 18:00:07 fedora kernel: usb 1-6: New USB device found, idVendor=1199, idProduct=9079, bcdDevice= 0.06
Nov 15 18:00:07 fedora kernel: usb 1-6: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Nov 15 18:00:07 fedora kernel: usb 1-6: Product: Sierra Wireless EM7455 Qualcomm Snapdragon X7 LTE-A
Nov 15 18:00:07 fedora kernel: usb 1-6: Manufacturer: Sierra Wireless, Incorporated
Nov 15 18:00:07 fedora kernel: usb 1-6: SerialNumber: LF72218337121020
Nov 15 18:00:07 fedora kernel: cdc_mbim 1-6:1.12: cdc-wdm0: USB WDM device
Nov 15 18:00:07 fedora kernel: cdc_mbim 1-6:1.12 wwan0: register 'cdc_mbim' at usb-0000:00:14.0-6, CDC MBIM, ca:36:dd:ae:f4:7a
Nov 15 18:00:07 fedora mtp-probe[56070]: checking bus 1, device 35: "/sys/devices/pci0000:00/0000:00:14.0/usb1/1-6"
Nov 15 18:00:07 fedora mtp-probe[56070]: bus: 1, device: 35 was not an MTP device
Nov 15 18:00:07 fedora audit[56024]: USER_AUTH pid=56024 uid=0 auid=1000 ses=2 subj=system_u:system_r:xdm_t:s0-s0:c0.c1023 msg='op=PAM:authentication grantors=>
Nov 15 18:00:07 fedora fprintd[56017]: libusb: error [udev_hotplug_event] ignoring udev action change
Nov 15 18:00:07 fedora systemd-udevd[56086]: Using default interface naming scheme 'v250'.
Nov 15 18:00:08 fedora ModemManager[966]: opening device...
Nov 15 18:00:22 fedora ModemManager[966]: <info>  [cdc-wdm0/mbim] MBIM device is not QMI capable
Nov 15 18:00:22 fedora ModemManager[966]: [/dev/cdc-wdm0] channel destroyed
Nov 15 18:00:22 fedora ModemManager[966]: <info>  [device /sys/devices/pci0000:00/0000:00:14.0/usb1/1-6] creating modem with plugin 'sierra' and '2' ports
Nov 15 18:00:22 fedora ModemManager[966]: <info>  [base-manager] modem for device '/sys/devices/pci0000:00/0000:00:14.0/usb1/1-6' successfully created
Nov 15 18:00:22 fedora ModemManager[966]: opening device...
Nov 15 18:00:22 fedora ModemManager[966]: [/dev/cdc-wdm0] Read max control message size from descriptors file: 4096
Nov 15 18:00:22 fedora ModemManager[966]: [/dev/cdc-wdm0] Opening device with flags 'version-info, proxy, mbim, expect-indications'...
Nov 15 18:00:22 fedora ModemManager[966]: [/dev/cdc-wdm0] created endpoint
Nov 15 18:00:22 fedora ModemManager[966]: [/dev/cdc-wdm0] creating MBIM device...
Nov 15 18:00:22 fedora ModemManager[966]: [/dev/cdc-wdm0] MBIM device created
Nov 15 18:00:22 fedora ModemManager[966]: [/dev/cdc-wdm0] opening MBIM device...

Logs after it no longer works:

Code:

c 13 10:23:56 fedora kernel: usb 1-6: new high-speed USB device number 124 using xhci_hcd
Dec 13 10:23:56 fedora kernel: usb 1-6: config 1 interface 0 altsetting 0 bulk endpoint 0x1 has invalid maxpacket 64
Dec 13 10:23:56 fedora kernel: usb 1-6: config 1 interface 0 altsetting 0 bulk endpoint 0x81 has invalid maxpacket 64
Dec 13 10:23:56 fedora kernel: usb 1-6: New USB device found, idVendor=1199, idProduct=9078, bcdDevice= 0.00
Dec 13 10:23:56 fedora kernel: usb 1-6: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Dec 13 10:23:56 fedora kernel: usb 1-6: Product: Sierra Wireless EM7455 Qualcomm
Dec 13 10:23:56 fedora kernel: usb 1-6: Manufacturer: Sierra Wireless, Incorporated
Dec 13 10:23:56 fedora kernel: usb 1-6: SerialNumber: LF72218337121020
Dec 13 10:23:56 fedora kernel: usb 1-6: USB disconnect, device number 124
Dec 13 10:23:57 fedora kernel: usb 1-6: new high-speed USB device number 126 using xhci_hcd
Dec 13 10:23:57 fedora kernel: usb 1-6: New USB device found, idVendor=1199, idProduct=9078, bcdDevice= 0.00
Dec 13 10:23:57 fedora kernel: usb 1-6: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Dec 13 10:23:57 fedora kernel: usb 1-6: Product: Sierra Wireless EM7455 Qualcomm
Dec 13 10:23:57 fedora kernel: usb 1-6: Manufacturer: Sierra Wireless, Incorporated
Dec 13 10:23:57 fedora kernel: usb 1-6: SerialNumber: LF72218337121020
Dec 13 10:23:57 fedora kernel: qcserial 1-6:1.0: Qualcomm USB modem converter detected
Dec 13 10:23:57 fedora kernel: usb 1-6: Qualcomm USB modem converter now attached to ttyUSB0
Dec 13 10:23:57 fedora mtp-probe[55459]: checking bus 1, device 126: "/sys/devices/pci0000:00/0000:00:14.0/usb1/1-6"
Dec 13 10:23:57 fedora mtp-probe[55459]: bus: 1, device: 126 was not an MTP device
Dec 13 10:23:58 fedora mtp-probe[55477]: checking bus 1, device 126: "/sys/devices/pci0000:00/0000:00:14.0/usb1/1-6"
Dec 13 10:23:58 fedora mtp-probe[55477]: bus: 1, device: 126 was not an MTP device
Dec 13 10:24:09 fedora ModemManager[943]: <warn>  [ttyUSB0/probe] failed to parse QCDM version info command result: -4
Dec 13 10:24:09 fedora ModemManager[943]: <warn>  [ttyUSB0/probe] failed to parse QCDM version info command result: -4
Dec 13 10:24:09 fedora ModemManager[943]: <info>  [device /sys/devices/pci0000:00/0000:00:14.0/usb1/1-6] creating modem with plugin 'generic' and '1' ports
Dec 13 10:24:09 fedora ModemManager[943]: <warn>  [plugin/generic] could not grab port ttyUSB0: Cannot add port 'tty/ttyUSB0', unhandled port type
Dec 13 10:24:09 fedora ModemManager[943]: <warn>  [base-manager] couldn't create modem for device '/sys/devices/pci0000:00/0000:00:14.0/usb1/1-6': Failed to find primary AT port
Dec 13 10:24:39 fedora kernel: usb 1-6: USB disconnect, device number 126
Dec 13 10:24:39 fedora kernel: qcserial ttyUSB0: Qualcomm USB modem converter now disconnected from ttyUSB0

I am afraid to try too many things without really knowing what I am doing, I have had my fare share of making things much worse when "just trying something out"...

Any advice on how to proceed?

Many thanks!

camorri · 12-19-2022, 12:39 PM

I don't see a rule for your product ID. When you greped for 9078, nothing showed up. My guess is you ahould have rule for the device.

Possibly vender doc could help you out. The following link may help.

https://source.sierrawireless.com/re....i730xVum.dpbs

business_kid · 12-19-2022, 01:42 PM

Welcome to LQ, pynting.

Did you have a udev rule in your previous install? Can you check?

pynting · 12-28-2022, 06:28 AM

Hi, and thanks.

I do not have backups of other directories than the home folder on my machine, so I was not able to look at the udev rules before the date it stopped working. It seems oddly specific that a rule for my card suddenly was taken out if it was there before... I don't know much about how the rules work, but would it not be the case that there is a general rule in there that might catch my card, or at least used to? I can try and run a live-iso and check if it has a udev rule for my card?

Thanks again for your assistance!

pynting · 01-02-2023, 04:33 AM

Hi again,
I tried to boot a live usb Fedora, and the problem actually persists even there, with the logs showing the same looping attempt to initialize the modem:

Code:

<warn>  [ttyUSB0/probe] failed to parse QCDM version info command result: -4
Jan 02 11:24:52 fedora ModemManager[853]: <warn>  [ttyUSB0/probe] failed to parse QCDM version info command result: -4
Jan 02 11:24:52 fedora ModemManager[853]: <info>  [device /sys/devices/pci0000:00/0000:00:14.0/usb1/1-6] creating modem with plugin 'generic' and '1' ports
Jan 02 11:24:52 fedora ModemManager[853]: <warn>  [plugin/generic] could not grab port ttyUSB0: Cannot add port 'tty/ttyUSB0', unhandled port type
Jan 02 11:24:52 fedora ModemManager[853]: <warn>  [base-manager] couldn't create modem for device '/sys/devices/pci0000:00/0000:00:14.0/usb1/1-6': Failed to find primary AT port

I checked, and the udev rules are the same there as well.

I also tried to remove and reinsert the module at the back of my laptop, but that had no effect either. Could it be the module that is faulty? It seems like the kernel grabs the module and prevents me from trying to connect to it via a serial terminal. Maybe if I was able to send AT commands to it, I could do a factory reset or something?