计算机数小时无法正常启动后，USB 端口突然不工作。
只能通过拔掉电源来关闭。我把它关了一整夜，但当我重新打开它时，它却无法识别 USB 拇指驱动器。
我如何找到问题并解决它？
编辑：这台电脑出现过多次断电，而且随着时间的推移，问题也越来越多，更新、升级和安装了许多不同的程序。不知道最近安装的一个或多个程序会造成什么后果。
$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 002: ID 0bda:0111 Realtek Semiconductor Corp. Card Reader
$ xinput
⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ ImPS/2 Generic Wheel Mouse id=9 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
↳ Power Button id=6 [slave keyboard (3)]
↳ Power Button id=7 [slave keyboard (3)]
↳ AT Translated Set 2 keyboard id=8 [slave keyboard (3)]
你发现其中有问题吗？
我把一个 U 盘插入 USB 端口，然后
$ dmesg | tail
[ 5352.260166] usb 2-6: device descriptor read/64, error -62
[ 5352.544120] usb 2-6: device descriptor read/64, error -62
[ 5352.824104] usb 2-6: new full-speed USB device number 4 using ohci_hcd
[ 5353.004050] usb 2-6: device descriptor read/64, error -62
[ 5353.288057] usb 2-6: device descriptor read/64, error -62
[ 5353.568076] usb 2-6: new full-speed USB device number 5 using ohci_hcd
[ 5353.976041] usb 2-6: device not accepting address 5, error -62
[ 5354.152037] usb 2-6: new full-speed USB device number 6 using ohci_hcd
[ 5354.560037] usb 2-6: device not accepting address 6, error -62
[ 5354.560058] hub 2-0:1.0: unable to enumerate USB device on port 6
还在 Ubuntu 软件中心检查了“udev”。它已经安装好了。
是不是已经损坏或者出现其他问题，导致 USB 端口无法正常工作？