my device is vantec nexstar gx: http://www.vantecusa.com/front/product/view_detail/182


dmesg:
[12020.656380] usb 1-1.1: new high speed USB device using ehci_hcd and address 12
[12020.800029] usb 1-1.1: configuration #1 chosen from 1 choice
[12020.800601] scsi7 : SCSI emulation for USB Mass Storage devices
[12020.801800] usb-storage: device found at 12
[12020.801807] usb-storage: waiting for device to settle before scanning
[12025.800330] usb-storage: device scan complete
[12025.801323] scsi 7:0:0:0: Direct-Access     WDC WD32 00JB-99AA0      08.0 PQ: 0 ANSI: 0
[12025.805526] sd 7:0:0:0: [sdd] 625142449 512-byte hardware sectors: (320 GB/298 GiB)
[12025.828368] sd 7:0:0:0: [sdd] Write Protect is off
[12025.828378] sd 7:0:0:0: [sdd] Mode Sense: 03 00 00 00
[12025.828439] sd 7:0:0:0: [sdd] Assuming drive cache: write through
[12025.834424] sd 7:0:0:0: [sdd] 625142449 512-byte hardware sectors: (320 GB/298 GiB)
[12025.835519] sd 7:0:0:0: [sdd] Write Protect is off
[12025.835528] sd 7:0:0:0: [sdd] Mode Sense: 03 00 00 00
[12025.835535] sd 7:0:0:0: [sdd] Assuming drive cache: write through
[12025.835546]  sdd: sdd1
[12025.849684] sd 7:0:0:0: [sdd] Attached SCSI disk
[12025.849866] sd 7:0:0:0: Attached scsi generic sg3 type 0
[12025.953475] sd 7:0:0:0: [sdd] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE,SUGGEST_OK
[12025.953482] sd 7:0:0:0: [sdd] Sense Key : Medium Error [current]
[12025.953487] sd 7:0:0:0: [sdd] Add. Sense: Recorded entity not found
[12025.953493] end_request: I/O error, dev sdd, sector 625142448
[12025.953496] __ratelimit: 128944 callbacks suppressed
[12025.953499] Buffer I/O error on device sdd, logical block 625142448
[12025.958095] sd 7:0:0:0: [sdd] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE,SUGGEST_OK
[12025.958099] sd 7:0:0:0: [sdd] Sense Key : Medium Error [current]
[12025.958103] sd 7:0:0:0: [sdd] Add. Sense: Recorded entity not found
[12025.958107] end_request: I/O error, dev sdd, sector 625142448
[12025.958110] Buffer I/O error on device sdd, logical block 625142448
[12025.965845] sd 7:0:0:0: [sdd] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE,SUGGEST_OK
[12025.965849] sd 7:0:0:0: [sdd] Sense Key : Medium Error [current]
[12025.965853] sd 7:0:0:0: [sdd] Add. Sense: Recorded entity not found
[12025.965858] end_request: I/O error, dev sdd, sector 625142448
[12025.965861] Buffer I/O error on device sdd, logical block 625142448
[12025.968965] sd 7:0:0:0: [sdd] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE,SUGGEST_OK
[12025.968969] sd 7:0:0:0: [sdd] Sense Key : Medium Error [current]
[12025.968973] sd 7:0:0:0: [sdd] Add. Sense: Recorded entity not found
[12025.968977] end_request: I/O error, dev sdd, sector 625142448
[12025.968980] Buffer I/O error on device sdd, logical block 625142448
[12025.972251] sd 7:0:0:0: [sdd] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE,SUGGEST_OK
[12025.972255] sd 7:0:0:0: [sdd] Sense Key : Medium Error [current]
[12025.972259] sd 7:0:0:0: [sdd] Add. Sense: Recorded entity not found
[12025.972263] end_request: I/O error, dev sdd, sector 625142448
[12025.972267] Buffer I/O error on device sdd, logical block 625142448
[12025.985105] sd 7:0:0:0: [sdd] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE,SUGGEST_OK
[12025.985109] sd 7:0:0:0: [sdd] Sense Key : Medium Error [current]
[12025.985113] sd 7:0:0:0: [sdd] Add. Sense: Recorded entity not found
[12025.985118] end_request: I/O error, dev sdd, sector 625142448
[12025.985121] Buffer I/O error on device sdd, logical block 625142448
[12025.988466] sd 7:0:0:0: [sdd] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE,SUGGEST_OK
[12025.988470] sd 7:0:0:0: [sdd] Sense Key : Medium Error [current]
[12025.988474] sd 7:0:0:0: [sdd] Add. Sense: Recorded entity not found
[12025.988478] end_request: I/O error, dev sdd, sector 625142448
[12025.988481] Buffer I/O error on device sdd, logical block 625142448

lsusb for that device:
Bus 001 Device 006: ID 05e3:0606 Genesys Logic, Inc. USB 2.0 Hub / D-Link DUB-H4 USB 2.0 Hub
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               2.00
  bDeviceClass            9 Hub
  bDeviceSubClass         0 Unused
  bDeviceProtocol         1 Single TT
  bMaxPacketSize0        64
  idVendor           0x05e3 Genesys Logic, Inc.
  idProduct          0x0606 USB 2.0 Hub / D-Link DUB-H4 USB 2.0 Hub
  bcdDevice            7.02
  iManufacturer           0
  iProduct                1 USB2.0 Hub
  iSerial                 0
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           25
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0
    bmAttributes         0xe0
      Self Powered
      Remote Wakeup
    MaxPower              100mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           1
      bInterfaceClass         9 Hub
      bInterfaceSubClass      0 Unused
      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     0x0001  1x 1 bytes
        bInterval              12
Hub Descriptor:
  bLength               9
  bDescriptorType      41
  nNbrPorts             4
  wHubCharacteristic 0x00e0
    Ganged power switching
    Ganged overcurrent protection
    TT think time 32 FS bits
    Port indicators
  bPwrOn2PwrGood       50 * 2 milli seconds
  bHubContrCurrent    100 milli Ampere
  DeviceRemovable    0x00
  PortPwrCtrlMask    0xff
 Hub Port Status:
   Port 1: 0000.0503 highspeed power enable connect
   Port 2: 0000.0100 power
   Port 3: 0000.0000
   Port 4: 0000.0100 power
Device Qualifier (for other device speed):
  bLength                10
  bDescriptorType         6
  bcdUSB               2.00
  bDeviceClass            9 Hub
  bDeviceSubClass         0 Unused
  bDeviceProtocol         0 Full speed (or root) hub
  bMaxPacketSize0        64
  bNumConfigurations      1
Device Status:     0x0003
  Self Powered
  Remote Wakeup Enabled