在内核更新至 3.3.6-030306 后，我的 USB 端口在 Ubuntu 12.04 下停止工作。我在启动过程中收到一条错误消息，提示“无法设置 xhci_hcd”。详情：
> dmesg | grep xhci
[ 0.906495] xhci_hcd 0000:04:00.0: found PCI INT A -> IRQ 10
[ 0.906509] xhci_hcd 0000:04:00.0: sharing IRQ 10 with 0000:00:1c.3
[ 0.906565] xhci_hcd 0000:04:00.0: xHCI Host Controller
[ 0.906600] xhci_hcd 0000:04:00.0: new USB bus registered, assigned bus number 3
[ 0.906648] xhci_hcd 0000:04:00.0: can't setup
[ 0.906652] xhci_hcd 0000:04:00.0: USB bus 3 deregistered
[ 0.906704] xhci_hcd 0000:04:00.0: init 0000:04:00.0 fail, -19
当我启动 Windows 7 时，USB 端口工作正常。我有一台 4 年前的 Dell XPS 15z，BIOS 是那时的：
> sudo dmidecode -s bios-release-date
01/13/2012
> sudo dmidecode -s bios-version
A09
任何帮助都将不胜感激，谢谢