The USB3 host controller involved:

    # lsusb -v -d 1d6b:0003 

    Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
    Device Descriptor:
    bLength                18
    bDescriptorType         1
    bcdUSB               3.00
    bDeviceClass            9 Hub
    bDeviceSubClass         0 
    bDeviceProtocol         3 
    bMaxPacketSize0         9
    idVendor           0x1d6b Linux Foundation
    idProduct          0x0003 3.0 root hub
    bcdDevice            3.18
    iManufacturer           3 Linux 3.18.9-gentoo xhci-hcd
    iProduct                2 xHCI Host Controller
    iSerial                 1 0000:02:00.0
    bNumConfigurations      1
    Configuration Descriptor:
        bLength                 9
        bDescriptorType         2
        wTotalLength           31
        bNumInterfaces          1
        bConfigurationValue     1
        iConfiguration          0 
        bmAttributes         0xe0
        Self Powered
        Remote Wakeup
        MaxPower                0mA
        Interface Descriptor:
        bLength                 9
        bDescriptorType         4
        bInterfaceNumber        0
        bAlternateSetting       0
        bNumEndpoints           1
        bInterfaceClass         9 Hub
        bInterfaceSubClass      0 
        bInterfaceProtocol      0 Full speed (or root) hub
        iInterface              0 
        Endpoint Descriptor:
            bLength                 7
            bDescriptorType         5
            bEndpointAddress     0x81  EP 1 IN
            bmAttributes            3
            Transfer Type            Interrupt
            Synch Type               None
            Usage Type               Data
            wMaxPacketSize     0x0004  1x 4 bytes
            bInterval              12
            bMaxBurst               0
    Hub Descriptor:
    bLength              12
    bDescriptorType      42
    nNbrPorts             2
    wHubCharacteristic 0x0009
        Per-port power switching
        Per-port overcurrent protection
    bPwrOn2PwrGood       10 * 2 milli seconds
    bHubContrCurrent      0 milli Ampere
    bHubDecLat          0.0 micro seconds
    wHubDelay             0 nano seconds
    DeviceRemovable    0x00
    Hub Port Status:
    Port 1: 0000.02a0 5Gbps power Rx.Detect
    Port 2: 0000.0203 5Gbps power U0 enable connect
    Binary Object Store Descriptor:
    bLength                 5
    bDescriptorType        15
    wTotalLength           15
    bNumDeviceCaps          1
    SuperSpeed USB Device Capability:
        bLength                10
        bDescriptorType        16
        bDevCapabilityType      3
        bmAttributes         0x02
        Latency Tolerance Messages (LTM) Supported
        wSpeedsSupported   0x0008
        Device can operate at SuperSpeed (5Gbps)
        bFunctionalitySupport   3
        Lowest fully-functional device speed is SuperSpeed (5Gbps)
        bU1DevExitLat           0 micro seconds
        bU2DevExitLat           0 micro seconds
    can't get debug descriptor: Resource temporarily unavailable
    Device Status:     0x0001
    Self Powered

    # lspci -vvv -s 02:00.0

    02:00.0 USB controller: Renesas Technology Corp. uPD720202 USB 3.0 Host Controller (rev 02) (prog-if 30 [XHCI])
        Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
        Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Latency: 0, Cache Line Size: 32 bytes
        Interrupt: pin A routed to IRQ 16
        Region 0: Memory at fddfe000 (64-bit, non-prefetchable) [size=8K]
        Capabilities: [50] Power Management version 3
            Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA PME(D0+,D1-,D2-,D3hot+,D3cold+)
            Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME-
        Capabilities: [70] MSI: Enable- Count=1/8 Maskable- 64bit+
            Address: 0000000000000000  Data: 0000
        Capabilities: [90] MSI-X: Enable+ Count=8 Masked-
            Vector table: BAR=0 offset=00001000
            PBA: BAR=0 offset=00001080
        Capabilities: [a0] Express (v2) Endpoint, MSI 00
            DevCap:	MaxPayload 128 bytes, PhantFunc 0, Latency L0s unlimited, L1 unlimited
                ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset-
            DevCtl:	Report errors: Correctable- Non-Fatal- Fatal- Unsupported-
                RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop+
                MaxPayload 128 bytes, MaxReadReq 512 bytes
            DevSta:	CorrErr+ UncorrErr- FatalErr- UnsuppReq+ AuxPwr+ TransPend-
            LnkCap:	Port #0, Speed 5GT/s, Width x1, ASPM L0s L1, Latency L0 <4us, L1 unlimited
                ClockPM+ Surprise- LLActRep- BwNot-
            LnkCtl:	ASPM Disabled; RCB 64 bytes Disabled- Retrain- CommClk+
                ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
            LnkSta:	Speed 2.5GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
            DevCap2: Completion Timeout: Not Supported, TimeoutDis+, LTR+, OBFF Not Supported
            DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR-, OBFF Disabled
            LnkCtl2: Target Link Speed: 5GT/s, EnterCompliance- SpeedDis-
                 Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
                 Compliance De-emphasis: -6dB
            LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete-, EqualizationPhase1-
                 EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest-
        Capabilities: [100 v1] Advanced Error Reporting
            UESta:	DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
            UEMsk:	DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
            UESvrt:	DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
            CESta:	RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+
            CEMsk:	RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+
            AERCap:	First Error Pointer: 00, GenCap- CGenEn- ChkCap- ChkEn-
        Capabilities: [150 v1] Latency Tolerance Reporting
            Max snoop latency: 0ns
            Max no snoop latency: 0ns
        Kernel driver in use: xhci_hcd
        Kernel modules: xhci_pci

The external HDD (note that it uses UAS):

    # lsusb -v -d 0480:d010

    Bus 004 Device 003: ID 0480:d010 Toshiba America Info. Systems, Inc. External Disk 3TB
    Device Descriptor:
      bLength                18
      bDescriptorType         1
      bcdUSB               3.00
      bDeviceClass            0 
      bDeviceSubClass         0 
      bDeviceProtocol         0 
      bMaxPacketSize0         9
      idVendor           0x0480 Toshiba America Info. Systems, Inc.
      idProduct          0xd010 External Disk 3TB
      bcdDevice            6.07
      iManufacturer           1 Toshiba
      iProduct                2 External USB 3.0
      iSerial                 3 20130421020612
      bNumConfigurations      1
      Configuration Descriptor:
        bLength                 9
        bDescriptorType         2
        wTotalLength           44
        bNumInterfaces          1
        bConfigurationValue     1
        iConfiguration          0 
        bmAttributes         0xc0
          Self Powered
        MaxPower                2mA
        Interface Descriptor:
          bLength                 9
          bDescriptorType         4
          bInterfaceNumber        0
          bAlternateSetting       0
          bNumEndpoints           2
          bInterfaceClass         8 Mass Storage
          bInterfaceSubClass      6 SCSI
          bInterfaceProtocol     80 Bulk-Only
          iInterface              0 
          Endpoint Descriptor:
            bLength                 7
            bDescriptorType         5
            bEndpointAddress     0x81  EP 1 IN
            bmAttributes            2
              Transfer Type            Bulk
              Synch Type               None
              Usage Type               Data
            wMaxPacketSize     0x0400  1x 1024 bytes
            bInterval               0
            bMaxBurst              14
          Endpoint Descriptor:
            bLength                 7
            bDescriptorType         5
            bEndpointAddress     0x02  EP 2 OUT
            bmAttributes            2
              Transfer Type            Bulk
              Synch Type               None
              Usage Type               Data
            wMaxPacketSize     0x0400  1x 1024 bytes
            bInterval               0
            bMaxBurst              14
    Binary Object Store Descriptor:
      bLength                 5
      bDescriptorType        15
      wTotalLength           22
      bNumDeviceCaps          2
      USB 2.0 Extension Device Capability:
        bLength                 7
        bDescriptorType        16
        bDevCapabilityType      2
        bmAttributes   0x00000002
          HIRD Link Power Management (LPM) Supported
      SuperSpeed USB Device Capability:
        bLength                10
        bDescriptorType        16
        bDevCapabilityType      3
        bmAttributes         0x00
        wSpeedsSupported   0x000e
          Device can operate at Full Speed (12Mbps)
          Device can operate at High Speed (480Mbps)
          Device can operate at SuperSpeed (5Gbps)
        bFunctionalitySupport   1
          Lowest fully-functional device speed is Full Speed (12Mbps)
        bU1DevExitLat          10 micro seconds
        bU2DevExitLat        2047 micro seconds
    can't get debug descriptor: Resource temporarily unavailable
    Device Status:     0x0001
      Self Powered