从 Ubuntu 16.04 升级到 18.04 后，我的 USB 3.0 集线器停止工作。当我插入集线器时，dmesg 显示：
$ dmesg
[ 481.971312] usb 3-1: USB disconnect, device number 2
[ 481.979323] usb 4-1: USB disconnect, device number 2
[ 493.939188] usb 4-1: new SuperSpeed USB device number 3 using xhci_hcd
[ 494.198398] usb 4-1: New USB device found, idVendor=2109, idProduct=0812
[ 494.198401] usb 4-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 494.198404] usb 4-1: Product: USB3.0 Hub
[ 494.198406] usb 4-1: Manufacturer: VIA Labs, Inc.
[ 494.199715] hub 4-1:1.0: USB hub found
[ 494.199873] hub 4-1:1.0: 4 ports detected
[ 494.322958] usb 3-1: new high-speed USB device number 3 using xhci_hcd
[ 494.473191] usb 3-1: New USB device found, idVendor=2109, idProduct=2812
[ 494.473194] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 494.473197] usb 3-1: Product: USB2.0 Hub
[ 494.473199] usb 3-1: Manufacturer: VIA Labs, Inc.
[ 494.473726] hub 3-1:1.0: USB hub found
[ 494.474125] hub 3-1:1.0: 4 ports detected
当我将 USB 棒插入集线器时，没有任何变化，但集线器状态指示灯发出信号，表示棒正在工作。当我直接插入棒时，它可以工作。
我已经尝试先启动然后连接集线器，结果相同。
编辑 14.09.18 21:50：
当我插入 USB 棒启动时，Hub 可以工作。当我未插入 USB 棒启动时，Hub 无法工作。
编辑 15.09.18 14:30：
当 Hub 连接到 PC 且 Hub 上连接有设备时，Hub 即可工作。如果 Hub 连接到 PC 且没有连接设备，则 Hub 无法工作。
这里是设备连接到集线器的 dmesg：
$ dmesg
[15631.321363] usb 3-1: USB disconnect, device number 2
[15631.325379] usb 4-1: USB disconnect, device number 2
[15635.397384] usb 4-1: new SuperSpeed USB device number 3 using xhci_hcd
[15635.656658] usb 4-1: New USB device found, idVendor=2109, idProduct=0812
[15635.656662] usb 4-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[15635.656664] usb 4-1: Product: USB3.0 Hub
[15635.656666] usb 4-1: Manufacturer: VIA Labs, Inc.
[15635.658178] hub 4-1:1.0: USB hub found
[15635.658302] hub 4-1:1.0: 4 ports detected
[15635.781248] usb 3-1: new high-speed USB device number 3 using xhci_hcd
[15635.930894] usb 3-1: New USB device found, idVendor=2109, idProduct=2812
[15635.930898] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[15635.930900] usb 3-1: Product: USB2.0 Hub
[15635.930902] usb 3-1: Manufacturer: VIA Labs, Inc.
[15635.931423] hub 3-1:1.0: USB hub found
[15635.931786] hub 3-1:1.0: 4 ports detected
[15636.045277] usb 4-1.1: new SuperSpeed USB device number 4 using xhci_hcd
[15636.066028] usb 4-1.1: New USB device found, idVendor=0781, idProduct=5580
[15636.066031] usb 4-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[15636.066034] usb 4-1.1: Product: Extreme
[15636.066036] usb 4-1.1: Manufacturer: SanDisk
[15636.066038] usb 4-1.1: SerialNumber: AA010301151733012970
[15636.085093] usb-storage 4-1.1:1.0: USB Mass Storage device detected
[15636.085206] scsi host6: usb-storage 4-1.1:1.0
[15636.085312] usbcore: registered new interface driver usb-storage
[15636.091297] usbcore: registered new interface driver uas
[15637.097724] scsi 6:0:0:0: Direct-Access SanDisk Extreme 0001 PQ: 0 ANSI: 6
[15637.098312] sd 6:0:0:0: Attached scsi generic sg4 type 0
[15637.098575] sd 6:0:0:0: [sdd] 122544516 512-byte logical blocks: (62.7 GB/58.4 GiB)
[15637.098821] sd 6:0:0:0: [sdd] Write Protect is off
[15637.098825] sd 6:0:0:0: [sdd] Mode Sense: 53 00 00 08
[15637.099029] sd 6:0:0:0: [sdd] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[15637.106686] sdd: sdd1
[15637.107824] sd 6:0:0:0: [sdd] Attached SCSI removable disk