我使用的是 Beaglebone Black，它装有 Debian 11，内核为 5.10 .168-ti-r71。我还连接了 GSM 调制解调器 SIM7000E。我正在尝试建立 PPP 连接。几周前我尝试过，没有遇到任何问题。今天我想再试一次，但在 syslog 文件中发现了一个奇怪的问题。
BeagleBone kernel: [ 416.877062] musb-hdrc musb-hdrc.1: Babble
BeagleBone kernel: [ 416.881245] musb-hdrc musb-hdrc.1: VBUS_ERROR in a_wait_bcon (89, <AValid), retry #1, port1 00010100
BeagleBone kernel: [ 416.881255] musb-hdrc musb-hdrc.1: Babble
BeagleBone kernel: [ 416.885854] usb 1-1: USB disconnect, device number 3
BeagleBone kernel: [ 416.886719] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
BeagleBone kernel: [ 416.886831] option 1-1:1.0: device disconnected
BeagleBone kernel: [ 416.893381] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
BeagleBone kernel: [ 416.893524] option 1-1:1.1: device disconnected
BeagleBone kernel: [ 416.903030] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
BeagleBone kernel: [ 416.903144] option 1-1:1.2: device disconnected
BeagleBone kernel: [ 416.904638] option1 ttyUSB3: GSM modem (1-port) converter now disconnected from ttyUSB3
BeagleBone kernel: [ 416.904765] option 1-1:1.3: device disconnected
BeagleBone kernel: [ 416.909438] option1 ttyUSB4: GSM modem (1-port) converter now disconnected from ttyUSB4
BeagleBone kernel: [ 416.909583] option 1-1:1.4: device disconnected
BeagleBone kernel: [ 416.910033] qmi_wwan 1-1:1.5 wwan0: unregister 'qmi_wwan' usb-musb-hdrc.1-1, WWAN/QMI device
BeagleBone kernel: [ 422.193485] usb 1-1: new high-speed USB device number 4 using musb-hdrc
BeagleBone kernel: [ 422.345237] usb 1-1: New USB device found, idVendor=1e0e, idProduct=9001, bcdDevice= 0.00
BeagleBone kernel: [ 422.345265] usb 1-1: New USB device strings: Mfr=3, Product=2, SerialNumber=4
BeagleBone kernel: [ 422.345275] usb 1-1: Product: SimTech SIM7000
BeagleBone kernel: [ 422.345284] usb 1-1: Manufacturer: SimTech, Incorporated
BeagleBone kernel: [ 422.345293] usb 1-1: SerialNumber: 1234567890ABCDEF
BeagleBone kernel: [ 422.358236] option 1-1:1.0: GSM modem (1-port) converter detected
BeagleBone kernel: [ 422.359020] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB0
BeagleBone kernel: [ 422.359843] option 1-1:1.1: GSM modem (1-port) converter detected
BeagleBone kernel: [ 422.362388] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB1
BeagleBone kernel: [ 422.363401] option 1-1:1.2: GSM modem (1-port) converter detected
BeagleBone kernel: [ 422.373416] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB2
BeagleBone kernel: [ 422.374494] option 1-1:1.3: GSM modem (1-port) converter detected
BeagleBone kernel: [ 422.375296] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB3
BeagleBone kernel: [ 422.376173] option 1-1:1.4: GSM modem (1-port) converter detected
BeagleBone kernel: [ 422.378195] usb 1-1: GSM modem (1-port) converter now attached to ttyUSB4
BeagleBone kernel: [ 422.386130] qmi_wwan 1-1:1.5: cdc-wdm0: USB WDM device
BeagleBone kernel: [ 422.397844] qmi_wwan 1-1:1.5 wwan0: register 'qmi_wwan' at usb-musb-hdrc.1-1, WWAN/QMI device, 06:8e:b>
BeagleBone systemd-udevd[1425]: Using default interface naming scheme 'v247'.
BeagleBone systemd-udevd[1425]: ethtool: autonegotiation is unset or enabled, the speed and duplex are not writable.
如果我在 ttyUSB2（调制解调器用于 AT 命令的端口）打开 minicom，我可以与调制解调器通信，但是当我输入 SIM 卡的 PIN 码时，minicom 会卡住并显示类似
Cannot open /dev/ttyUSB2!
我也尝试使用另一个调制解调器 SIM7600E，但出现了与上述相同的问题。我重新启动了系统，打开/关闭电源，检查了电源，但仍然没有任何效果。我的系统中没有安装 ethtool。对于上述问题，您有什么想法以及如何解决它们？