USB 设备编号随时间变化

Question

我正在尝试在我的 RP 上使用 camre USB 设备 - Logitech, Inc. 网络摄像头 C270。当我直接连接到RP的USB端口时，其他USB设备停止工作（例如WIFI设备）我猜测这是由于相机的功耗造成的。所以我使用电源外包USB集线器将相机连接到RP，

我可以看到 RP 很好地识别集线器 (lsusb)，但摄像头设备快速显示并从 lsusb 输出中消失。当它显示时它总是具有不同的设备编号......

这里附上一些输出的示例lsusb- 一个接一个地输入 -

Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
Bus 001 Device 004: ID 214b:7000
Bus 001 Device 005: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
Bus 001 Device 007: ID 148f:5370 Ralink Technology, Corp. RT5370 Wireless Adapter
Bus 001 Device 049: ID 046d:0825 Logitech, Inc. Webcam C270

lsusb

Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
Bus 001 Device 004: ID 214b:7000
Bus 001 Device 005: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
Bus 001 Device 007: ID 148f:5370 Ralink Technology, Corp. RT5370 Wireless Adapter

lsusb
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
Bus 001 Device 004: ID 214b:7000
Bus 001 Device 005: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
Bus 001 Device 007: ID 148f:5370 Ralink Technology, Corp. RT5370 Wireless Adapter
Bus 001 Device 055: ID 046d:0825 Logitech, Inc. Webcam C270

lsusb
Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
Bus 001 Device 004: ID 214b:7000
Bus 001 Device 005: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
Bus 001 Device 007: ID 148f:5370 Ralink Technology, Corp. RT5370 Wireless Adapter
Bus 001 Device 060: ID 046d:0825 Logitech, Inc. Webcam C270