日志如下，使用的是quectel-CM工具，只要联网成功之后就会一直断开然后重新连接。
[root@luckfox root]# microcom -s 115200 /dev/ttyUSB2
OK
Quectel
EC200A
Revision: EC200ACNHAR01A14M16
OK
[ 1303.849419] usb 1-1: USB disconnect, device number 16
[ 1303.849689] cdc_ether 1-1:1.0 usb0: unregister ‘cdc_ether’ usb-xhci-hcd.0.auto-1, CDC Ethernet Device
[root@luckfox root]# [ 1303.853583] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[ 1303.853673] option 1-1:1.2: device disconnected
[ 1303.854198] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[ 1303.854271] option 1-1:1.3: device disconnected
[ 1303.860204] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[ 1303.860295] option 1-1:1.4: device disconnected
[ 1304.204905] usb 1-1: new high-speed USB device number 17 using xhci-hcd
[ 1304.354973] usb 1-1: Device not responding to setup address.
[ 1304.574933] usb 1-1: Device not responding to setup address.
[ 1304.794911] usb 1-1: device not accepting address 17, error -71
[ 1305.164912] usb 1-1: new high-speed USB device number 18 using xhci-hcd
[ 1305.937312] usb 1-1: Device not responding to setup address.
[ 1306.154945] usb 1-1: Device not responding to setup address.
[ 1306.374909] usb 1-1: device not accepting address 18, error -71
[ 1306.375131] usb usb1-port1: attempt power cycle
[ 1306.844921] usb 1-1: new high-speed USB device number 19 using xhci-hcd
[ 1306.903881] cdc_ether 1-1:1.0 usb0: register ‘cdc_ether’ at usb-xhci-hcd.0.auto-1, CDC Ethernet Device, 02:0c:29:a3:9b:6d
[ 1306.906152] option 1-1:1.2: GSM modem (1-port) converter detected
[ 1306.906904] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
[ 1306.908353] option 1-1:1.3: GSM modem (1-port) converter detected
[ 1306.909096] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
[ 1306.910484] option 1-1:1.4: GSM modem (1-port) converter detected
[ 1306.910808] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB2
[ 1308.515231] usb 1-1: USB disconnect, device number 19
[ 1308.515411] cdc_ether 1-1:1.0 usb0: unregister ‘cdc_ether’ usb-xhci-hcd.0.auto-1, CDC Ethernet Device
[ 1308.516812] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[ 1308.516890] option 1-1:1.2: device disconnected
[ 1308.517373] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[ 1308.517444] option 1-1:1.3: device disconnected
[ 1308.517898] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[ 1308.517968] option 1-1:1.4: device disconnected
[ 1308.874917] usb 1-1: new high-speed USB device number 20 using xhci-hcd
[ 1309.244928] usb 1-1: device descriptor read/64, error -71
[ 1309.734935] usb 1-1: device descriptor read/64, error -71
[ 1310.004910] usb 1-1: new high-speed USB device number 21 using xhci-hcd
[ 1311.644943] usb 1-1: device descriptor read/64, error -71
[ 1311.959950] cdc_ether 1-1:1.0 usb0: register ‘cdc_ether’ at usb-xhci-hcd.0.auto-1, CDC Ethernet Device, 02:0c:29:a3:9b:6d
[ 1311.962017] option 1-1:1.2: GSM modem (1-port) converter detected
[ 1311.962784] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
[ 1311.964297] option 1-1:1.3: GSM modem (1-port) converter detected
[ 1311.964612] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
[ 1311.967094] option 1-1:1.4: GSM modem (1-port) converter detected
[ 1311.967411] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB2
[ 1313.159111] usb 1-1: USB disconnect, device number 21
[ 1313.159289] cdc_ether 1-1:1.0 usb0: unregister ‘cdc_ether’ usb-xhci-hcd.0.auto-1, CDC Ethernet Device
[ 1313.162465] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[ 1313.162557] option 1-1:1.2: device disconnected
[ 1313.163088] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[ 1313.163211] option 1-1:1.3: device disconnected
[ 1313.166122] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[ 1313.166213] option 1-1:1.4: device disconnected
[ 1313.514908] usb 1-1: new high-speed USB device number 22 using xhci-hcd
[ 1313.719574] cdc_ether 1-1:1.0 usb0: register ‘cdc_ether’ at usb-xhci-hcd.0.auto-1, CDC Ethernet Device, 02:0c:29:a3:9b:6d
[ 1313.720682] option 1-1:1.2: GSM modem (1-port) converter detected
[ 1313.720999] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
[ 1313.721746] option 1-1:1.3: GSM modem (1-port) converter detected
[ 1313.722052] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
[ 1313.722830] option 1-1:1.4: GSM modem (1-port) converter detected
[ 1313.725627] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB2
[ 1313.920121] usb 1-1: USB disconnect, device number 22
[ 1313.920304] cdc_ether 1-1:1.0 usb0: unregister ‘cdc_ether’ usb-xhci-hcd.0.auto-1, CDC Ethernet Device
[ 1313.923897] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[ 1313.923987] option 1-1:1.2: device disconnected
[ 1313.925495] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[ 1313.925585] option 1-1:1.3: device disconnected
[ 1313.929817] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[ 1313.929916] option 1-1:1.4: device disconnected
[ 1314.284903] usb 1-1: new high-speed USB device number 23 using xhci-hcd
[ 1314.487594] cdc_ether 1-1:1.0 usb0: register ‘cdc_ether’ at usb-xhci-hcd.0.auto-1, CDC Ethernet Device, 02:0c:29:a3:9b:6d
[ 1314.488685] option 1-1:1.2: GSM modem (1-port) converter detected
[ 1314.488986] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
[ 1314.489740] option 1-1:1.3: GSM modem (1-port) converter detected
[ 1314.490047] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
[ 1314.490832] option 1-1:1.4: GSM modem (1-port) converter detected
[ 1314.493657] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB2
[root@luckfox root]# udhcpc -i usb0
udhcpc: started, v1.36.1
udhcpc: broadcasting discover
udhcpc: broadcasting select for 10.38.163.166, server 169.254.0.1
udhcpc: lease of 10.38.163.166 obtained from 169.254.0.1, lease time 86400
deleting routers
adding dns 211.136.150.86
adding dns 211.136.150.88
[root@luckfox root]# [ 1496.947634] usb 1-1: USB disconnect, device number 23
[ 1496.948026] cdc_ether 1-1:1.0 usb0: unregister ‘cdc_ether’ usb-xhci-hcd.0.auto-1, CDC Ethernet Device
[ 1496.953232] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[ 1496.953321] option 1-1:1.2: device disconnected
[ 1496.955515] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[ 1496.955604] option 1-1:1.3: device disconnected
[ 1496.958419] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[ 1496.958512] option 1-1:1.4: device disconnected
p[ 1497.324913] usb 1-1: new high-speed USB device number 24 using xhci-hcd
[ 1497.527895] cdc_ether 1-1:1.0 usb0: register ‘cdc_ether’ at usb-xhci-hcd.0.auto-1, CDC Ethernet Device, 02:0c:29:a3:9b:6d
[ 1497.529924] option 1-1:1.2: GSM modem (1-port) converter detected
[ 1497.530228] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
[ 1497.530988] option 1-1:1.3: GSM modem (1-port) converter detected
[ 1497.531303] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
[ 1497.533683] option 1-1:1.4: GSM modem (1-port) converter detected
[ 1497.534004] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB2
[ 1498.505614] usb 1-1: USB disconnect, device number 24
[ 1498.505795] cdc_ether 1-1:1.0 usb0: unregister ‘cdc_ether’ usb-xhci-hcd.0.auto-1, CDC Ethernet Device
[ 1498.507206] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[ 1498.507291] option 1-1:1.2: device disconnected
[ 1498.507757] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[ 1498.507835] option 1-1:1.3: device disconnected
[ 1498.508285] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[ 1498.508355] option 1-1:1.4: device disconnected
[ 1498.864908] usb 1-1: new high-speed USB device number 25 using xhci-hcd
[ 1499.063611] cdc_ether 1-1:1.0 usb0: register ‘cdc_ether’ at usb-xhci-hcd.0.auto-1, CDC Ethernet Device, 02:0c:29:a3:9b:6d
[ 1499.064708] option 1-1:1.2: GSM modem (1-port) converter detected
[ 1499.065424] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
[ 1499.066221] option 1-1:1.3: GSM modem (1-port) converter detected
[ 1499.066528] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
[ 1499.067303] option 1-1:1.4: GSM modem (1-port) converter detected
[ 1499.069820] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB2
[ 1500.685480] usb 1-1: USB disconnect, device number 25
[ 1500.685662] cdc_ether 1-1:1.0 usb0: unregister ‘cdc_ether’ usb-xhci-hcd.0.auto-1, CDC Ethernet Device
[ 1500.687063] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[ 1500.687147] option 1-1:1.2: device disconnected
[ 1500.687617] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[ 1500.687690] option 1-1:1.3: device disconnected
[ 1500.688145] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[ 1500.688214] option 1-1:1.4: device disconnected
[ 1501.034906] usb 1-1: new high-speed USB device number 26 using xhci-hcd
[ 1501.239557] cdc_ether 1-1:1.0 usb0: register ‘cdc_ether’ at usb-xhci-hcd.0.auto-1, CDC Ethernet Device, 02:0c:29:a3:9b:6d
[ 1501.240685] option 1-1:1.2: GSM modem (1-port) converter detected
[ 1501.240994] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
[ 1501.241745] option 1-1:1.3: GSM modem (1-port) converter detected
[ 1501.242051] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
[ 1501.242823] option 1-1:1.4: GSM modem (1-port) converter detected
[ 1501.245556] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB2
[ 1502.705862] usb 1-1: USB disconnect, device number 26
[ 1502.706041] cdc_ether 1-1:1.0 usb0: unregister ‘cdc_ether’ usb-xhci-hcd.0.auto-1, CDC Ethernet Device
[ 1502.709943] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[ 1502.710037] option 1-1:1.2: device disconnected
[ 1502.712568] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[ 1502.712658] option 1-1:1.3: device disconnected
[ 1502.714556] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[ 1502.714643] option 1-1:1.4: device disconnected
[ 1503.084904] usb 1-1: new high-speed USB device number 27 using xhci-hcd
[ 1503.287558] cdc_ether 1-1:1.0 usb0: register ‘cdc_ether’ at usb-xhci-hcd.0.auto-1, CDC Ethernet Device, 02:0c:29:a3:9b:6d
[ 1503.288655] option 1-1:1.2: GSM modem (1-port) converter detected
[ 1503.288959] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
[ 1503.289695] option 1-1:1.3: GSM modem (1-port) converter detected
[ 1503.289996] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
[ 1503.290764] option 1-1:1.4: GSM modem (1-port) converter detected
[ 1503.293639] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB2
[ 1503.565362] usb 1-1: USB disconnect, device number 27
[ 1503.565541] cdc_ether 1-1:1.0 usb0: unregister ‘cdc_ether’ usb-xhci-hcd.0.auto-1, CDC Ethernet Device
[ 1503.566927] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[ 1503.567004] option 1-1:1.2: device disconnected
[ 1503.567474] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[ 1503.567546] option 1-1:1.3: device disconnected
[ 1503.568010] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[ 1503.568079] option 1-1:1.4: device disconnected
[ 1503.914990] usb 1-1: new high-speed USB device number 28 using xhci-hcd
[ 1504.119513] cdc_ether 1-1:1.0 usb0: register ‘cdc_ether’ at usb-xhci-hcd.0.auto-1, CDC Ethernet Device, 02:0c:29:a3:9b:6d
[ 1504.120618] option 1-1:1.2: GSM modem (1-port) converter detected
[ 1504.120923] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
[ 1504.121671] option 1-1:1.3: GSM modem (1-port) converter detected
[ 1504.121978] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
[ 1504.122743] option 1-1:1.4: GSM modem (1-port) converter detected
[ 1504.125568] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB2
[ 1504.365360] usb 1-1: USB disconnect, device number 28
[ 1504.365541] cdc_ether 1-1:1.0 usb0: unregister ‘cdc_ether’ usb-xhci-hcd.0.auto-1, CDC Ethernet Device
[ 1504.366941] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[ 1504.367024] option 1-1:1.2: device disconnected
[ 1504.367503] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[ 1504.367576] option 1-1:1.3: device disconnected
[ 1504.369331] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[ 1504.369468] option 1-1:1.4: device disconnected
[ 1504.714907] usb 1-1: new high-speed USB device number 29 using xhci-hcd
[ 1504.919512] cdc_ether 1-1:1.0 usb0: register ‘cdc_ether’ at usb-xhci-hcd.0.auto-1, CDC Ethernet Device, 02:0c:29:a3:9b:6d
[ 1504.920600] option 1-1:1.2: GSM modem (1-port) converter detected
[ 1504.920910] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
[ 1504.921646] option 1-1:1.3: GSM modem (1-port) converter detected
[ 1504.921955] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
[ 1504.922716] option 1-1:1.4: GSM modem (1-port) converter detected
[ 1504.925672] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB2
[ 1505.186103] usb 1-1: USB disconnect, device number 29
[ 1505.186287] cdc_ether 1-1:1.0 usb0: unregister ‘cdc_ether’ usb-xhci-hcd.0.auto-1, CDC Ethernet Device
[ 1505.187677] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[ 1505.187762] option 1-1:1.2: device disconnected
[ 1505.188235] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[ 1505.188311] option 1-1:1.3: device disconnected
[ 1505.188769] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[ 1505.188844] option 1-1:1.4: device disconnected
[ 1505.554911] usb 1-1: new high-speed USB device number 30 using xhci-hcd
[ 1505.751528] cdc_ether 1-1:1.0 usb0: register ‘cdc_ether’ at usb-xhci-hcd.0.auto-1, CDC Ethernet Device, 02:0c:29:a3:9b:6d
[ 1505.752636] option 1-1:1.2: GSM modem (1-port) converter detected
[ 1505.752948] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
[ 1505.753691] option 1-1:1.3: GSM modem (1-port) converter detected
[ 1505.753990] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
[ 1505.754768] option 1-1:1.4: GSM modem (1-port) converter detected
[ 1505.757732] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB2