为了开发，我买了一个带有 28 个 USB 集线器的 USB 集线器：Manhattan MondoHub II。该设备由外部电源供电，足以满足我的用例。
在 USB 集线器上，连接了 15 个开发板（STMicro Nucleo 板）。基本上，一旦您将开发板插入 USB 端口，ST-Link v2 芯片就会将底层微控制器的闪存作为 USB 驱动器公开，您可以在其上拖放固件文件。然后用该固件刷新电路板。我需要自动闪烁它们。因此，我将每块板连接到集线器并运行一个闪烁所有内容的脚本。
问题是并非所有 15 个连接的设备都被识别。其中只有 11 个。dmesg引发有关 USB 主机控制器没有足够资源的错误。
在内部，USB 集线器似乎由多个 USB 集线器组成。
dmesg当我插入 USB 集线器时，没有连接任何设备：
[269831.218406] usb 2-3: new high-speed USB device number 91 using xhci_hcd
[269831.369806] usb 2-3: New USB device found, idVendor=2109, idProduct=2811
[269831.369813] usb 2-3: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[269831.369817] usb 2-3: Product: USB2.0 Hub
[269831.369821] usb 2-3: Manufacturer: VIA Labs, Inc.
[269831.370918] hub 2-3:1.0: USB hub found
[269831.371195] hub 2-3:1.0: 4 ports detected
[269831.678404] usb 2-3.1: new high-speed USB device number 92 using xhci_hcd
[269831.790645] usb 2-3.1: New USB device found, idVendor=1a40, idProduct=0201
[269831.790650] usb 2-3.1: New USB device strings: Mfr=0, Product=1, SerialNumber=0
[269831.790654] usb 2-3.1: Product: USB 2.0 Hub [MTT]
[269831.791150] hub 2-3.1:1.0: USB hub found
[269831.791177] hub 2-3.1:1.0: 7 ports detected
[269831.886375] usb 2-3.2: new high-speed USB device number 93 using xhci_hcd
[269831.998500] usb 2-3.2: New USB device found, idVendor=1a40, idProduct=0201
[269831.998504] usb 2-3.2: New USB device strings: Mfr=0, Product=1, SerialNumber=0
[269831.998506] usb 2-3.2: Product: USB 2.0 Hub [MTT]
[269831.998942] hub 2-3.2:1.0: USB hub found
[269831.998964] hub 2-3.2:1.0: 7 ports detected
[269832.090378] usb 2-3.3: new high-speed USB device number 94 using xhci_hcd
[269832.202654] usb 2-3.3: New USB device found, idVendor=1a40, idProduct=0201
[269832.202658] usb 2-3.3: New USB device strings: Mfr=0, Product=1, SerialNumber=0
[269832.202660] usb 2-3.3: Product: USB 2.0 Hub [MTT]
[269832.203232] hub 2-3.3:1.0: USB hub found
[269832.203258] hub 2-3.3:1.0: 7 ports detected
[269832.294400] usb 2-3.4: new high-speed USB device number 95 using xhci_hcd
[269832.415440] usb 2-3.4: New USB device found, idVendor=14cd, idProduct=8601
[269832.415449] usb 2-3.4: New USB device strings: Mfr=1, Product=3, SerialNumber=0
[269832.415454] usb 2-3.4: Product: USB 2.0 Hub
[269832.415458] usb 2-3.4: Manufacturer: USB Device
[269832.416721] hub 2-3.4:1.0: USB hub found
[269832.416838] hub 2-3.4:1.0: 4 ports detected
断开连接时：
[269873.242343] usb 2-3: USB disconnect, device number 91
[269873.242349] usb 2-3.1: USB disconnect, device number 92
[269873.243596] usb 2-3.2: USB disconnect, device number 93
[269873.244672] usb 2-3.3: USB disconnect, device number 94
[269873.245725] usb 2-3.4: USB disconnect, device number 95
然后我连接板接板。板 1 到 11 被识别并导致此类消息：
[269950.734094] usb 2-3.2.1: new full-speed USB device number 103 using xhci_hcd
[269950.856137] usb 2-3.2.1: New USB device found, idVendor=0483, idProduct=374b
[269950.856140] usb 2-3.2.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[269950.856142] usb 2-3.2.1: Product: STM32 STLink
[269950.856144] usb 2-3.2.1: Manufacturer: STMicroelectronics
[269950.856146] usb 2-3.2.1: SerialNumber: 0671FF323532543457250836
[269950.911199] usb-storage 2-3.2.1:1.1: USB Mass Storage device detected
[269950.911377] scsi host5: usb-storage 2-3.2.1:1.1
[269950.911809] cdc_acm 2-3.2.1:1.2: ttyACM2: USB ACM device
[269951.942405] scsi 5:0:0:0: Direct-Access MBED microcontroller 1.0 PQ: 0 ANSI: 2
[269951.942686] sd 5:0:0:0: Attached scsi generic sg4 type 0
[269951.942980] sd 5:0:0:0: [sdd] 2080 512-byte logical blocks: (1.06 MB/1.02 MiB)
[269951.943876] sd 5:0:0:0: [sdd] Write Protect is off
[269951.943887] sd 5:0:0:0: [sdd] Mode Sense: 03 00 00 00
[269951.944137] sd 5:0:0:0: [sdd] No Caching mode page found
[269951.944143] sd 5:0:0:0: [sdd] Assuming drive cache: write through
[269951.963779] sd 5:0:0:0: [sdd] Attached SCSI removable disk
连接第 12 块板时，无法识别。日志：
[270155.277574] usb 2-3.2.6: new full-speed USB device number 112 using xhci_hcd
[270155.407457] usb 2-3.2.6: New USB device found, idVendor=0483, idProduct=374b
[270155.407464] usb 2-3.2.6: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[270155.407468] usb 2-3.2.6: Product: STM32 STLink
[270155.407472] usb 2-3.2.6: Manufacturer: STMicroelectronics
[270155.407476] usb 2-3.2.6: SerialNumber: 066DFF323532543457074843
[270155.408451] usb 2-3.2.6: Not enough host controller resources for new device state.
[270155.408681] usb 2-3.2.6: can't set config #1, error -12
这里发生了什么？我是否受到 USB 协议、集线器或内核/驱动程序的限制？
在联想 ThinkPad E550 上运行 Ubuntu Budgie '18.04.1 LTS (Bionic Beaver)'。
如果需要，将获取更多日志。完整的日志文件：https ://pastebin.com/BarBHwnc