Thanks for the fast reply. I tried the following:
- Soldered additional capacitors onto the power supply to stabilize the power control (both on 3.3V and 5.0V side).
- Tried to raise the 3.3 V supply voltage in order to counteract minor voltage drops (Datasheet claims that the modem supports input voltage range up to 3.6 V)
- I detected, that there was a Voltage drop in the USB cables (0.4V over 10 cm!!), which caused the power supply to not work correctly
-> I soldered an additional, external powersupply onto the Adapter with enough capacity. It should be now more than stable (3 A continous and 4 A peak on 3.3V side).
But, the modem/usb-stack still crashes. Now, when I run the ‘at!scact=1,1’ command. Note, that the SINR is below 0 dB at this point of time. When I unplug the device and reattach, the modem seems NOT to have rebooted due to the external power supply (the Current time still runs and Reset Counter did not increase).
I either receive the nonzero urb -71 error, or the usb device resets.
Modem Status before crash:
!GSTATUS:
Current Time: 1736 Temperature: 26
Reset Counter: 1 Mode: ONLINE
System mode: LTE PS state: Attached
LTE band: B20 LTE bw: 10 MHz
LTE Rx chan: 6300 LTE Tx chan: 24300
LTE CA state: NOT ASSIGNED
EMM state: Registered Normal Service
RRC state: RRC Idle
IMS reg state: No Srv
PCC RxM RSSI: -66 RSRP (dBm): -103
PCC RxD RSSI: -98 RSRP (dBm): -140
Tx Power: 0 TAC: B093 (45203)
RSRQ (dB): -20.0 Cell ID: 00CE7C03 (13532163)
SINR (dB): -8.2Dmesg extract of the crash 1:
GobiSerial driver ttyUSB1: usb_serial_generic_write_bulk_callback - nonzero urb status: -71Dmesg extract of the crash 2:
[Fr Jan 26 11:30:51 2018] GobiNet 2-1:1.8 eth0: register 'GobiNet' at usb-0000:00:14.0-1, GobiNet Ethernet Device, e2:42:62:11:ba:4c
[Fr Jan 26 11:30:51 2018] USB Speed : USB 3.0
[Fr Jan 26 11:30:51 2018] GobiNet 2-1:1.8 lte0: renamed from eth0
[Fr Jan 26 11:30:51 2018] IPv6: ADDRCONF(NETDEV_UP): lte0: link is not ready
[Fr Jan 26 11:30:51 2018] GobiNet 2-1:1.8 lte0: kevent 12 may have been dropped
[Fr Jan 26 11:30:51 2018] IPv6: ADDRCONF(NETDEV_UP): lte0: link is not ready
[Fr Jan 26 11:30:56 2018] creating qcqmi0
[Fr Jan 26 11:30:56 2018] RawIP mode
[Fr Jan 26 11:31:06 2018] IPv6: ADDRCONF(NETDEV_CHANGE): lte0: link becomes ready
[Fr Jan 26 11:31:06 2018] GobiNet 2-1:1.8 lte0: kevent 12 may have been dropped
[Fr Jan 26 11:31:07 2018] usb 2-1: USB disconnect, device number 29
[Fr Jan 26 11:31:07 2018] GobiSerial driver ttyUSB0: GobiSerial converter now disconnected from ttyUSB0
[Fr Jan 26 11:31:07 2018] GobiSerial 2-1:1.0: device disconnected
[Fr Jan 26 11:31:07 2018] GobiSerial driver ttyUSB1: GobiSerial converter now disconnected from ttyUSB1
[Fr Jan 26 11:31:07 2018] GobiSerial 2-1:1.3: device disconnected
[Fr Jan 26 11:31:07 2018] GobiNet 2-1:1.8 lte0: unregister 'GobiNet' usb-0000:00:14.0-1, GobiNet Ethernet Device
[Fr Jan 26 11:31:07 2018] usb 2-1: new SuperSpeed USB device number 30 using xhci_hcd
[Fr Jan 26 11:31:07 2018] usb 2-1: config 1 has an invalid interface number: 3 but max is 2
[Fr Jan 26 11:31:07 2018] usb 2-1: config 1 has an invalid interface number: 8 but max is 2
[Fr Jan 26 11:31:07 2018] usb 2-1: config 1 has no interface number 1
[Fr Jan 26 11:31:07 2018] usb 2-1: config 1 has no interface number 2
[Fr Jan 26 11:31:07 2018] usb 2-1: Enable of device-initiated U1 failed.
[Fr Jan 26 11:31:07 2018] usb 2-1: Enable of device-initiated U2 failed.
[Fr Jan 26 11:31:07 2018] usb 2-1: Disable of device-initiated U1 failed.
[Fr Jan 26 11:31:07 2018] usb 2-1: Disable of device-initiated U2 failed.
[Fr Jan 26 11:31:07 2018] usb 2-1: Enable of device-initiated U1 failed.
[Fr Jan 26 11:31:07 2018] usb 2-1: Enable of device-initiated U2 failed.
[Fr Jan 26 11:31:07 2018] GobiSerial 2-1:1.0: GobiSerial converter detected
[Fr Jan 26 11:31:07 2018] usb 2-1: GobiSerial converter now attached to ttyUSB0
[Fr Jan 26 11:31:07 2018] usb 2-1: Disable of device-initiated U1 failed.
[Fr Jan 26 11:31:07 2018] usb 2-1: Disable of device-initiated U2 failed.
[Fr Jan 26 11:31:07 2018] usb 2-1: Enable of device-initiated U1 failed.
[Fr Jan 26 11:31:07 2018] usb 2-1: Enable of device-initiated U2 failed.
[Fr Jan 26 11:31:07 2018] GobiSerial 2-1:1.3: GobiSerial converter detected
[Fr Jan 26 11:31:07 2018] usb 2-1: GobiSerial converter now attached to ttyUSB1
[Fr Jan 26 11:31:07 2018] usb 2-1: Disable of device-initiated U1 failed.
[Fr Jan 26 11:31:07 2018] usb 2-1: Disable of device-initiated U2 failed.
[Fr Jan 26 11:31:07 2018] usb 2-1: Enable of device-initiated U1 failed.
[Fr Jan 26 11:31:07 2018] usb 2-1: Enable of device-initiated U2 failed.
[Fr Jan 26 11:31:07 2018] GobiNet 2-1:1.8 eth0: register 'GobiNet' at usb-0000:00:14.0-1, GobiNet Ethernet Device, e2:42:62:11:ba:4c
[Fr Jan 26 11:31:07 2018] USB Speed : USB 3.0
[Fr Jan 26 11:31:07 2018] GobiNet 2-1:1.8 lte0: renamed from eth0
[Fr Jan 26 11:31:07 2018] IPv6: ADDRCONF(NETDEV_UP): lte0: link is not ready
[Fr Jan 26 11:31:09 2018] usb 2-1: USB disconnect, device number 30
[Fr Jan 26 11:31:09 2018] GobiSerial driver ttyUSB0: GobiSerial converter now disconnected from ttyUSB0
[Fr Jan 26 11:31:09 2018] GobiSerial 2-1:1.0: device disconnected
[Fr Jan 26 11:31:09 2018] GobiSerial driver ttyUSB1: GobiSerial converter now disconnected from ttyUSB1
[Fr Jan 26 11:31:09 2018] GobiSerial 2-1:1.3: device disconnected
[Fr Jan 26 11:31:09 2018] GobiNet 2-1:1.8 lte0: unregister 'GobiNet' usb-0000:00:14.0-1, GobiNet Ethernet Device
[Fr Jan 26 11:31:09 2018] usb 2-1: new SuperSpeed USB device number 31 using xhci_hcd
[Fr Jan 26 11:31:09 2018] usb 2-1: config 1 has an invalid interface number: 3 but max is 2
[Fr Jan 26 11:31:09 2018] usb 2-1: config 1 has an invalid interface number: 8 but max is 2
[Fr Jan 26 11:31:09 2018] usb 2-1: config 1 has no interface number 1
[Fr Jan 26 11:31:09 2018] usb 2-1: config 1 has no interface number 2
[Fr Jan 26 11:31:09 2018] usb 2-1: Enable of device-initiated U1 failed.
[Fr Jan 26 11:31:09 2018] usb 2-1: Enable of device-initiated U2 failed.
[Fr Jan 26 11:31:09 2018] usb 2-1: Disable of device-initiated U1 failed.
[Fr Jan 26 11:31:09 2018] usb 2-1: Disable of device-initiated U2 failed.
[Fr Jan 26 11:31:09 2018] usb 2-1: Enable of device-initiated U1 failed.
[Fr Jan 26 11:31:09 2018] usb 2-1: Enable of device-initiated U2 failed.
[Fr Jan 26 11:31:09 2018] GobiNet 2-1:1.8 eth0: register 'GobiNet' at usb-0000:00:14.0-1, GobiNet Ethernet Device, e2:42:62:11:ba:4c
[Fr Jan 26 11:31:09 2018] USB Speed : USB 3.0
[Fr Jan 26 11:31:09 2018] GobiNet 2-1:1.8 lte0: renamed from eth0
[Fr Jan 26 11:31:09 2018] IPv6: ADDRCONF(NETDEV_UP): lte0: link is not ready
[Fr Jan 26 11:31:09 2018] GobiNet 2-1:1.8 lte0: kevent 12 may have been dropped
[Fr Jan 26 11:31:09 2018] IPv6: ADDRCONF(NETDEV_UP): lte0: link is not ready
[Fr Jan 26 11:31:24 2018] creating qcqmi0
[Fr Jan 26 11:31:24 2018] RawIP mode
...