Hi all,
I got a weird problem with my openwrt setup and don't know how to troubleshoot it any further:
My setup consists of an gl.inet gl-mt3000 which is connected to a quectel rm520n-gl m.2 modem in an external m.2-to-usb enclosure.
The assembly with the m.2-to-usb enclosure and the modem in usb mode connected to i.e. my windows11 works flawlessly.
In openwrt I'm able to establish and even use the connection and it's also quite stable until I try to do a throughput test against website "www.wieistmeineip.de". While downloading succeeds at rates around 75-100Mbit/s the modem reproducibly gets disconnected from usb when the upload part oft the throughput test starts. I tried both qmi and mbim mode - error remains the same. Also I already switched openwrt firmwares from stable 24.10.0 to latest SNAPSHOT to no avail. As told before in windows the test succeeds at least in mbim mode with exact same setup regarding the modem part.
Doing a " logread -f" all I'm left with is messages indicating the usb device got disconnected from openwrt machine like:
Sun Mar 9 20:50:37 2025 kern.info kernel: [ 1349.113561] usb 1-1: USB
disconnect, device number 6
Sun Mar 9 20:50:37 2025 kern.info kernel: [ 1349.118809] option1
ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
Sun Mar 9 20:50:37 2025 kern.info kernel: [ 1349.126994] option
1-1:1.0: device disconnected
Sun Mar 9 20:50:37 2025 kern.info kernel: [ 1349.131910] option1
ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
Sun Mar 9 20:50:37 2025 kern.info kernel: [ 1349.140023] option
1-1:1.1: device disconnected
Sun Mar 9 20:50:37 2025 daemon.info ModemManager[14860]: hotplug:
remove serial interface ttyUSB0: event processed
Sun Mar 9 20:50:37 2025 kern.info kernel: [ 1349.146593] option1
ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
Sun Mar 9 20:50:37 2025 kern.info kernel: [ 1349.154753] option
1-1:1.2: device disconnected
Sun Mar 9 20:50:37 2025 kern.info kernel: [ 1349.159715] option1
ttyUSB3: GSM modem (1-port) converter now disconnected from ttyUSB3
Sun Mar 9 20:50:37 2025 kern.info kernel: [ 1349.167958] option
1-1:1.3: device disconnected
Sun Mar 9 20:50:37 2025 kern.info kernel: [ 1349.173047] qmi_wwan
1-1:1.4 wwan0: unregister 'qmi_wwan' usb-11200000.usb-1, WWAN/QMI device
Sun Mar 9 20:50:37 2025 daemon.notice [3170]: <msg> [base-manager] port
ttyUSB0 released by device '/sys/devices/platform/soc/11200000.usb/usb1/1-1'
Sun Mar 9 20:50:37 2025 daemon.notice netifd: Interface 'wwan_4' is
disabled
....
After that event usb device almost instantly gets rediscovered and also most of the time dials in again without user intervention.
I suppose this could be a voltage problm or bandwidth related but don't know how to troubleshoot thia any further - probably someone came across this or similar issues and can help me out.
Best regards,
supergonzo74