Noticed crash in driver in EM7421 module. It works fine for few days before noticing crash in dmesg logs. watchdog timeout with the transmit queue timed out, and the modem stops responding to AT channel too. Only recovery is router reboot. [425494.194583] ------------[ cut here ]------------ [425…

would you consider to use RMNET (set in AT!USBCOMP) instead of MBIM? if so, you can see here: [image] Example on establishing data connection by AT!SCACT via MBPL R20 driver Development tools If anyone is interested in the background - here’s a PoC patch for dhclient I wr…

[image] katamadhu: NETDEV WATCHDOG: wwan0 (cdc_mbim): transmit queue 0 timed out Hi @katamadhu , I am also facing the same issue sometimes on my module. Can you please suggest how you solved this issue? NETDEV WATCHDOG: wwan0 (cdc_mbim): transmit queue 0 timed out THanks, Arti

can you route the USB cable to linux PC? This can isolate if problem comes from your hardware.

Similar issue is observed on the ubuntu PC.

Then this could be your hardware issue as i don’t see such problem with EM9291 in Ubuntu 18 PC. I can establish data connection with mbim-network command: [image] Packet statistics of EM9293 and EM7431 how about using qmicli? owner@ubuntu:~$ sudo mbim-netwo…

I am also not facing any issues with mbim driver. I am facing issues with qmi driver

why did you need to use QMI driver? QMI communication also works in MBIM driver.

Hi @jyijyi , Beacause I have found the “qmi_wwan.c” driver file on the Sierra website. Initially, I started with this driver file only, but faced issues in getting the WWAN interface. Thanks, Arti Thanks, Arti

you can ignore this file if you are using MBIM interface

EM7421 failed in NETDEV WATCHDOG: wwan0 (cdc_mbim): transmit queue 0 timed out

IoT Modules

jyijyi July 14, 2021, 1:49am 2

would you consider to use RMNET (set in AT!USBCOMP) instead of MBIM?

if so, you can see here:

Topic		Replies	Views
EM9190 cdc_mbim 4-3:1.0 wwan0: NETDEV WATCHDOG: CPU: 0: transmit queue 0 timed out MC/EM Series driver	1	98	November 28, 2025
MC7421 QmiDevice: Transaction timed out MC/EM Series	25	1956	June 13, 2023
EM7455 , WWAN/QMI: RX and TX stuck after a while MC/EM Series	11	3652	September 13, 2018
Setting up EM9291 Module IoT Modules faq , driver	35	494	May 1, 2026
EM7430 LTE module some Question MC/EM Series	1	689	January 10, 2020

EM7421 failed in NETDEV WATCHDOG: wwan0 (cdc_mbim): transmit queue 0 timed out

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