我的笔记本电脑（Gigabyte Aero 15 Classic XA）运行 Ubuntu 21.10（20.04 上也是一样），出现了一个奇怪的问题。当我插入 USB 3 棒时，只能获得 USB 2 速度。但是，在启动前插入同一根棒时，我可以获得 USB 3 速度。
lsusb -t确认：
启动后保持连接：
/: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 10000M
/: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 480M
/: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/8p, 10000M
|__ Port 5: Dev 5, If 0, Class=Mass Storage, Driver=usb-storage, 5000M
/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/16p, 480M
|__ Port 3: Dev 14, If 0, Class=Mass Storage, Driver=usb-storage, 480M <- the stick
|__ Port 9: Dev 9, If 0, Class=Video, Driver=uvcvideo, 480M
|__ Port 9: Dev 9, If 1, Class=Video, Driver=uvcvideo, 480M
|__ Port 11: Dev 10, If 2, Class=Human Interface Device, Driver=usbhid, 12M
|__ Port 11: Dev 10, If 0, Class=Human Interface Device, Driver=usbhid, 12M
|__ Port 11: Dev 10, If 3, Class=Human Interface Device, Driver=usbhid, 12M
|__ Port 11: Dev 10, If 1, Class=Human Interface Device, Driver=usbhid, 12M
|__ Port 14: Dev 4, If 0, Class=Wireless, Driver=btusb, 12M
|__ Port 14: Dev 4, If 1, Class=Wireless, Driver=btusb, 12M
在启动之前：
/: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 10000M
/: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 480M
/: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/8p, 10000M
|__ Port 3: Dev 2, If 0, Class=Mass Storage, Driver=usb-storage, 5000M
|__ Port 5: Dev 3, If 0, Class=Mass Storage, Driver=usb-storage, 5000M <- the stick
/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/16p, 480M
|__ Port 9: Dev 2, If 0, Class=Video, Driver=uvcvideo, 480M
|__ Port 9: Dev 2, If 1, Class=Video, Driver=uvcvideo, 480M
|__ Port 11: Dev 3, If 2, Class=Human Interface Device, Driver=usbhid, 12M
|__ Port 11: Dev 3, If 0, Class=Human Interface Device, Driver=usbhid, 12M
|__ Port 11: Dev 3, If 3, Class=Human Interface Device, Driver=usbhid, 12M
|__ Port 11: Dev 3, If 1, Class=Human Interface Device, Driver=usbhid, 12M
|__ Port 14: Dev 4, If 0, Class=Wireless, Driver=btusb, 12M
|__ Port 14: Dev 4, If 1, Class=Wireless, Driver=btusb, 12M
任何 USB 记忆棒都会受到影响。那么是什么原因造成的呢？同一个物理 USB 端口上的同一个记忆棒怎么会根据插入时间位于不同的总线上呢？
系统信息
PROCESSOR: Intel Core i7-9750H @ 4.50GHz
Core Count: 6
Thread Count: 12
Extensions: SSE 4.2 + AVX2 + AVX + RDRAND + FSGSBASE
Cache Size: 12288 MB
Microcode: 0xea
Core Family: Kaby/Coffee/Whiskey Lake
Scaling Driver: intel_pstate powersave (EPP: balance_performance)
GRAPHICS: Gigabyte Intel UHD 630 CFL GT2 8GB
BAR1 / Visible vRAM: 256 MiB
OpenGL: 4.6 Mesa 21.2.6
Display Driver: NVIDIA
Monitor: LQ156M1JW03
Screen: 1920x1080
MOTHERBOARD: GIGABYTE AERO 15 Classic-XA
BIOS Version: B04
Chipset: Intel Cannon Lake PCH
Audio: Realtek ALC255
Network: Qualcomm Atheros Killer E2500 + Intel Cannon Lake PCH CNVi WiFi
你好，西蒙