一些设备（例如键盘）在我购买的廉价 USB 集线器上运行良好，但我尝试将 USB 调制解调器放在同一个集线器上却失败了，但如果我直接放到笔记本电脑上，它就可以正常工作。
我目前的发现：
lsusb显示我的 USB 调制解调器为“未知制造商集线器”：
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 024: ID 0cf3:e005 Qualcomm Atheros Communications
Bus 001 Device 007: ID 0bda:0129 Realtek Semiconductor Corp. RTS5129 Card Reader Controller
Bus 001 Device 005: ID 1bcf:2c01 Sunplus Innovation Technology Inc. Integrated Webcam
Bus 001 Device 006: ID 05ac:024f Apple, Inc. USB2.0 HUB
Bus 001 Device 004: ID 05ac:1006 Apple, Inc. Hub in Aluminum Keyboard
Bus 001 Device 060: ID 1c9e:98ff OMEGA TECHNOLOGY Keyboard Hub
Bus 001 Device 058: ID 0a05:7211 Unknown Manufacturer hub
Bus 001 Device 056: ID 0a05:7211 Unknown Manufacturer hub
Bus 001 Device 025: ID 0a05:7211 Unknown Manufacturer hub
Bus 001 Device 002: ID 1ea7:0064 SHARKOON Technologies GmbH 2.4G Mouse
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
当我插入 USB 调制解调器时，我得到以下信息dmesg：
[ +0,000003] usb 1-2: Product: USB2.0 HUB
[ +0,001094] hub 1-2:1.0: USB hub found
[ +0,000122] hub 1-2:1.0: 4 ports detected
[ +0,413173] usb 1-2.2: new full-speed USB device number 26 using xhci_hcd
[ +0,101104] usb 1-2.2: New USB device found, idVendor=0a05, idProduct=7211, bcdDevice= 1.00
[ +0,000005] usb 1-2.2: New USB device strings: Mfr=0, Product=1, SerialNumber=0
[ +0,000003] usb 1-2.2: Product: USB2.0 HUB
[ +0,001181] hub 1-2.2:1.0: USB hub found
[ +0,000122] hub 1-2.2:1.0: 4 ports detected
[ +0,365607] usb 1-2.2: USB disconnect, device number 26
[ +0,023730] usb 1-2.2-port2: attempt power cycle
[ +0,000004] usb 1-2.2-port2: failed to disable port power
[ +0,079775] usb 1-2.2: new full-speed USB device number 31 using xhci_hcd
[ +0,100949] usb 1-2.2: New USB device found, idVendor=0a05, idProduct=7211, bcdDevice= 1.00
[ +0,000008] usb 1-2.2: New USB device strings: Mfr=0, Product=1, SerialNumber=0
[ +0,000005] usb 1-2.2: Product: USB2.0 HUB
[ +0,001275] hub 1-2.2:1.0: USB hub found
[ +0,000091] hub 1-2.2:1.0: 4 ports detected
[ +0,365617] usb 1-2.2: USB disconnect, device number 31
[ +0,023818] usb 1-2.2-port2: attempt power cycle
[ +0,000005] usb 1-2.2-port2: failed to disable port power
[ +0,079672] usb 1-2.2: new full-speed USB device number 36 using xhci_hcd
[ +0,101122] usb 1-2.2: New USB device found, idVendor=0a05, idProduct=7211, bcdDevice= 1.00
[ +0,000005] usb 1-2.2: New USB device strings: Mfr=0, Product=1, SerialNumber=0
[ +0,000003] usb 1-2.2: Product: USB2.0 HUB
[ +0,001347] hub 1-2.2:1.0: USB hub found
[ +0,000156] hub 1-2.2:1.0: 4 ports detected
[ +0,365261] usb 1-2.2: USB disconnect, device number 36
[ +0,019916] usb 1-2.2-port2: attempt power cycle
[ +0,000004] usb 1-2.2-port2: failed to disable port power
[ +0,079775] usb 1-2.2: new full-speed USB device number 41 using xhci_hcd
[ +0,100975] usb 1-2.2: New USB device found, idVendor=0a05, idProduct=7211, bcdDevice= 1.00
[ +0,000006] usb 1-2.2: New USB device strings: Mfr=0, Product=1, SerialNumber=0
[ +0,000004] usb 1-2.2: Product: USB2.0 HUB
[ +0,001247] hub 1-2.2:1.0: USB hub found
[ +0,000084] hub 1-2.2:1.0: 4 ports detected
[ +0,365724] usb 1-2.2: USB disconnect, device number 41
[ +0,019775] usb 1-2.2-port2: attempt power cycle
[ +0,000004] usb 1-2.2-port2: failed to disable port power
[ +0,079791] usb 1-2.2: new full-speed USB device number 46 using xhci_hcd
[ +0,101193] usb 1-2.2: New USB device found, idVendor=0a05, idProduct=7211, bcdDevice= 1.00
[ +0,000006] usb 1-2.2: New USB device strings: Mfr=0, Product=1, SerialNumber=0
[ +0,000003] usb 1-2.2: Product: USB2.0 HUB
[ +0,001321] hub 1-2.2:1.0: USB hub found
[ +0,000127] hub 1-2.2:1.0: 4 ports detected
[ +0,369393] usb 1-2.2: USB disconnect, device number 46
[ +0,019740] usb 1-2.2-port2: attempt power cycle
[ +0,000005] usb 1-2.2-port2: failed to disable port power
[ +0,083775] usb 1-2.2: new full-speed USB device number 51 using xhci_hcd
[ +0,101092] usb 1-2.2: New USB device found, idVendor=0a05, idProduct=7211, bcdDevice= 1.00
[ +0,000006] usb 1-2.2: New USB device strings: Mfr=0, Product=1, SerialNumber=0
[ +0,000004] usb 1-2.2: Product: USB2.0 HUB
[ +0,001412] hub 1-2.2:1.0: USB hub found
[ +0,000182] hub 1-2.2:1.0: 4 ports detected
[ +0,465403] usb 1-2.2: USB disconnect, device number 51
[ +0,019599] usb 1-2.2-port2: attempt power cycle
[ +0,000004] usb 1-2.2-port2: failed to disable port power
[ +0,079807] usb 1-2.2: new full-speed USB device number 56 using xhci_hcd
[ +0,101686] usb 1-2.2: New USB device found, idVendor=0a05, idProduct=7211, bcdDevice= 1.00
[ +0,000006] usb 1-2.2: New USB device strings: Mfr=0, Product=1, SerialNumber=0
[ +0,000004] usb 1-2.2: Product: USB2.0 HUB
[ +0,001440] hub 1-2.2:1.0: USB hub found
[ +0,000108] hub 1-2.2:1.0: 4 ports detected
[ +0,084618] usb 1-2.3: new full-speed USB device number 57 using xhci_hcd
[ +0,101979] usb 1-2.3: not running at top speed; connect to a high speed hub
[ +0,004366] usb 1-2.3: New USB device found, idVendor=1c9e, idProduct=98ff, bcdDevice= 0.00
[ +0,000006] usb 1-2.3: New USB device strings: Mfr=3, Product=2, SerialNumber=4
[ +0,000003] usb 1-2.3: Manufacturer: USB Modem
[ +0,000003] usb 1-2.3: SerialNumber: 1234567890ABCDEF
[ +0,309238] usb 1-2.2.2: new full-speed USB device number 58 using xhci_hcd
[ +0,000443] usb-storage 1-2.3:1.0: USB Mass Storage device detected
[ +0,000145] scsi host2: usb-storage 1-2.3:1.0
[ +0,000093] usbcore: registered new interface driver usb-storage
[ +0,001772] usbcore: registered new interface driver uas
[ +0,103439] usb 1-2.2.2: New USB device found, idVendor=0a05, idProduct=7211, bcdDevice= 1.00
[ +0,000006] usb 1-2.2.2: New USB device strings: Mfr=0, Product=1, SerialNumber=0
[ +0,000004] usb 1-2.2.2: Product: USB2.0 HUB
[ +0,001477] hub 1-2.2.2:1.0: USB hub found
[ +0,000151] hub 1-2.2.2:1.0: 4 ports detected
[ +0,897740] scsi 2:0:0:0: Direct-Access USBModem Disk 2.31 PQ: 0 ANSI: 2
[ +0,000866] scsi 2:0:0:1: CD-ROM USBModem Disk 2.31 PQ: 0 ANSI: 2
[ +0,000829] sd 2:0:0:0: Attached scsi generic sg1 type 0
[ +0,003979] sr 2:0:0:1: [sr0] scsi-1 drive
[ +0,000007] cdrom: Uniform CD-ROM driver Revision: 3.20
[ +0,016596] sr 2:0:0:1: Attached scsi CD-ROM sr0
[ +0,000097] sr 2:0:0:1: Attached scsi generic sg2 type 5
[ +0,009099] sd 2:0:0:0: [sdb] Attached SCSI removable disk
[ +0,126863] usb 1-2.3: reset full-speed USB device number 57 using xhci_hcd
[ +0,101838] usb 1-2.3: device firmware changed
[ +0,000259] sr 2:0:0:1: [sr0] tag#0 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK cmd_age=0s
[ +0,000008] sr 2:0:0:1: [sr0] tag#0 CDB: Read(10) 28 00 00 02 1b fc 00 00 02 00
[ +0,000008] blk_update_request: I/O error, dev sr0, sector 552944 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
[ +0,000264] usb 1-2.3: USB disconnect, device number 57
[ +0,013331] sr 2:0:0:1: [sr0] tag#0 FAILED Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK cmd_age=0s
[ +0,000011] sr 2:0:0:1: [sr0] tag#0 CDB: Read(10) 28 00 00 02 1b fc 00 00 02 00
[ +0,000009] blk_update_request: I/O error, dev sr0, sector 552944 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[ +0,000011] Buffer I/O error on dev sr0, logical block 69118, async page read
[ +0,000211] sr 2:0:0:1: [sr0] tag#0 FAILED Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK cmd_age=0s
[ +0,000008] sr 2:0:0:1: [sr0] tag#0 CDB: Read(10) 28 00 00 00 00 00 00 00 02 00
[ +0,000007] blk_update_request: I/O error, dev sr0, sector 0 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
[ +0,000071] sr 2:0:0:1: [sr0] tag#0 FAILED Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK cmd_age=0s
[ +0,000007] sr 2:0:0:1: [sr0] tag#0 CDB: Read(10) 28 00 00 00 00 00 00 00 02 00
[ +0,000006] blk_update_request: I/O error, dev sr0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[ +0,000007] Buffer I/O error on dev sr0, logical block 0, async page read
[ +0,000065] sr 2:0:0:1: [sr0] tag#0 FAILED Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK cmd_age=0s
[ +0,000007] sr 2:0:0:1: [sr0] tag#0 CDB: Read(10) 28 00 00 00 00 00 00 00 02 00
[ +0,000005] blk_update_request: I/O error, dev sr0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[ +0,000006] Buffer I/O error on dev sr0, logical block 0, async page read
[ +0,000055] sr 2:0:0:1: [sr0] tag#0 FAILED Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK cmd_age=0s
[ +0,000007] sr 2:0:0:1: [sr0] tag#0 CDB: Read(10) 28 00 00 00 00 00 00 00 02 00
[ +0,000005] blk_update_request: I/O error, dev sr0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[ +0,000005] Buffer I/O error on dev sr0, logical block 0, async page read
[ +0,000057] sr 2:0:0:1: [sr0] tag#0 FAILED Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK cmd_age=0s
[ +0,000007] sr 2:0:0:1: [sr0] tag#0 CDB: Read(10) 28 00 00 00 00 00 00 00 02 00
[ +0,000005] blk_update_request: I/O error, dev sr0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[ +0,000005] Buffer I/O error on dev sr0, logical block 0, async page read
[ +0,000058] sr 2:0:0:1: [sr0] tag#0 FAILED Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK cmd_age=0s
[ +0,000006] sr 2:0:0:1: [sr0] tag#0 CDB: Read(10) 28 00 00 00 00 00 00 00 02 00
[ +0,000005] blk_update_request: I/O error, dev sr0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[ +0,000005] Buffer I/O error on dev sr0, logical block 0, async page read
[ +0,000053] sr 2:0:0:1: [sr0] tag#0 FAILED Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK cmd_age=0s
[ +0,000007] sr 2:0:0:1: [sr0] tag#0 CDB: Read(10) 28 00 00 00 00 00 00 00 02 00
[ +0,000005] blk_update_request: I/O error, dev sr0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[ +0,000005] Buffer I/O error on dev sr0, logical block 0, async page read
[ +0,000053] sr 2:0:0:1: [sr0] tag#0 FAILED Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK cmd_age=0s
[ +0,000007] sr 2:0:0:1: [sr0] tag#0 CDB: Read(10) 28 00 00 00 00 00 00 00 02 00
[ +0,000005] blk_update_request: I/O error, dev sr0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
[ +0,000005] Buffer I/O error on dev sr0, logical block 0, async page read
[ +0,000049] Buffer I/O error on dev sr0, logical block 0, async page read
[ +0,000047] Buffer I/O error on dev sr0, logical block 0, async page read
[ +0,214899] usb 1-2.3: new full-speed USB device number 59 using xhci_hcd
[ +0,105040] usb 1-2.3: not running at top speed; connect to a high speed hub
[ +0,000922] usb 1-2.3: unable to read config index 0 descriptor/start: -71
[ +0,000005] usb 1-2.3: can't read configurations, error -71
[ +0,077926] usb 1-2.3: new full-speed USB device number 60 using xhci_hcd
[ +0,104540] usb 1-2.3: New USB device found, idVendor=1c9e, idProduct=98ff, bcdDevice= 0.00
[ +0,000007] usb 1-2.3: New USB device strings: Mfr=3, Product=2, SerialNumber=4
[ +0,000004] usb 1-2.3: SerialNumber: 1234567890ABCDEF
[ +0,004444] usb 1-2.3: can't set config #1, error -71
第一个错误是：
[ +0,101838] usb 1-2.3: device firmware changed
[ +0,000259] sr 2:0:0:1: [sr0] tag#0 FAILED Result: hostbyte=DID_ERROR driverbyte=DRIVER_OK cmd_age=0s
[ +0,000008] sr 2:0:0:1: [sr0] tag#0 CDB: Read(10) 28 00 00 02 1b fc 00 00 02 00
[ +0,000008] blk_update_request: I/O error, dev sr0, sector 552944 op 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
很多错误。Ubuntu 识别了 USB 调制解调器，但随后立即“关闭”。
关于如何进一步调试这个问题，有什么提示吗？
我不应该省下这笔钱而买一个像样的 USB 集线器。