[4G][Hotplug] Plug out USB 4G module prompt "resubmit read urb failed"

For Developers
1

Hello！

I am using OpenWRT 15.05 runs on MT7628 with 4G USB module that is simcom SIM7600CE.

And I confused very much by the hot-plug, when I plug out the USB module first time after booting, I got the blow error, and after plug back, got the second block message output. The ttyUSB1~ttyUSB5 appear in /dev but I cannot communicate with them, I tried to run "minicom -D /dev/ttyUSB2" but cannot input anything, and also failed to dial up with command "echo -e "AT$QCRMCALL=1,1\r" > /dev/ttyUSB2".

From the error message, looks like failed to request an asynchronize transmit, but I don't know what is wrong. Only reboot OpenWRT(by "reboot" command or re-power), the USB 4G module works fine again.

I searched from google but have not fixed it yet. Can you help me? Thanks very much.

root@OpenWrt:/# [  300.160000] usb 1-1: USB disconnect, device number 2
[  300.170000] option1 ttyUSB0: usb_wwan_indat_callback: resubmit read urb failed. (-19)
[  300.190000] option1 ttyUSB0: usb_wwan_indat_callback: resubmit read urb failed. (-19)
[  300.200000] option1 ttyUSB0: usb_wwan_indat_callback: resubmit read urb failed. (-19)
[  300.220000] option1 ttyUSB0: usb_wwan_indat_callback: resubmit read urb failed. (-19)
[  300.240000] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[  300.250000] option 1-1:1.0: device disconnected
[  300.260000] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[  300.280000] option 1-1:1.1: device disconnected
[  300.290000] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[  300.300000] option 1-1:1.2: device disconnected
[  300.310000] option1 ttyUSB3: GSM modem (1-port) converter now disconnected from ttyUSB3
[  300.330000] option 1-1:1.3: device disconnected
[  300.340000] option1 ttyUSB4: GSM modem (1-port) converter now disconnected from ttyUSB4
[  300.350000] option 1-1:1.4: device disconnected
[  300.380000] simcom_wwan 1-1:1.5 wwan0: unregister 'simcom_wwan' usb-101c0000.ehci-1, SIMCOM wwan/QMI device

[ 5413.160000] simcom_wwan: probe of 1-1:1.0 failed with error -22
[ 5413.170000] option 1-1:1.0: GSM modem (1-port) converter detected
[ 5413.190000] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
[ 5413.200000] simcom_wwan: probe of 1-1:1.1 failed with error -22
[ 5413.210000] option 1-1:1.1: GSM modem (1-port) converter detected
[ 5413.220000] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB2
[ 5413.240000] simcom_wwan: probe of 1-1:1.2 failed with error -22
[ 5413.250000] option 1-1:1.2: GSM modem (1-port) converter detected
[ 5413.260000] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB3
[ 5413.280000] simcom_wwan: probe of 1-1:1.3 failed with error -22
[ 5413.290000] option 1-1:1.3: GSM modem (1-port) converter detected
[ 5413.300000] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB4
[ 5413.320000] simcom_wwan: probe of 1-1:1.4 failed with error -22
[ 5413.330000] option 1-1:1.4: GSM modem (1-port) converter detected
[ 5413.340000] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB5
[ 5413.370000] simcom usbnet bind here
[ 5413.380000] simcom_wwan 1-1:1.5 wwan0: register 'simcom_wwan' at usb-101c0000.ehci-1, SIMCOM wwan/QMI device, 02:40:9d:3d:fb:07
[ 5413.400000] simcom_wwan 1-1:1.5 wwan0: kevent 12 may have been dropped

Best Regard,
Jakebo

2

Hello, did you solve the problem?

3

In nov '18 when this was posted, 15.05 was 2.5 years old, I sure hope he has upgraded since then.

4

FWIW, I believe those messages are secondary symptoms and that the only real error is the USB disconnect

This could be a cable/connection issue, but is most often the result of an unexpected modem reboot.

Either because the firmware crashed, or more likely because a power spike caused the 3.3V supply voltage to drop too much. This is a very common problem for 4G and 5G modems, which can have moderate power requirements on average but still need insane peak currents.