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[Brad Figg <brad.figg@xxxxxxxxxxxxx>]

This bug is missing log files that will aid in diagnosing the problem.
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apport-collect 1582759

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This change has been made by an automated script, maintained by the
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** Changed in: linux (Ubuntu)
       Status: New => Incomplete

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https://bugs.launchpad.net/bugs/1582759

Title:
  Unexpected low write rate with Lexar JumpDrive P20 64GB flash drives

Status in linux package in Ubuntu:
  Incomplete

Bug description:
  We are hitting an unexpected low write rate with Lexar JumpDrive P20
  64GB flash drives connected via USB 3.0 on multiple machines and
  across multiple kernels (3.13, 4.4). Expected is a write rate of 270
  MB/s and we only get 45 MB/s. Under Mac OS X and Windows we get the
  expected write rate of 270 MB/s. The read rate is as expected at 400
  MB/s on all operating systems.

  
  Lexar JumpDrive P20 details:
  http://www.lexar.com/flash-drives/jumpdrive-p20

  
  Tested machines:
  * HP Z440
  * Lenovo ThinkPad X250

  
  Tested kernels:
  * 3.13 (Trusty)
  * 4.4 (Xenial)

  
  lsusb details:

  $ lsusb -t
  /:  Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/4p, 5000M
      |__ Port 2: Dev 2, If 0, Class=Mass Storage, Driver=usb-storage, 5000M  <-- USB 3.0
  /:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/11p, 480M
      |__ Port 1: Dev 2, If 0, Class=Vendor Specific Class, Driver=, 12M
      |__ Port 8: Dev 4, If 0, Class=Video, Driver=uvcvideo, 480M
      |__ Port 8: Dev 4, If 1, Class=Video, Driver=uvcvideo, 480M
  /:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/3p, 480M
      |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/8p, 480M


  $ sudo lsusb -d 05dc:a212 -vvv

  Bus 003 Device 002: ID 05dc:a212 Lexar Media, Inc. 
  Device Descriptor:
    bLength                18
    bDescriptorType         1
    bcdUSB               3.00
    bDeviceClass            0 (Defined at Interface level)
    bDeviceSubClass         0 
    bDeviceProtocol         0 
    bMaxPacketSize0         9
    idVendor           0x05dc Lexar Media, Inc.
    idProduct          0xa212 
    bcdDevice            1.00
    iManufacturer           1 Lexar
    iProduct                2 USB Flash Drive
    iSerial                 3 0C5E8B182D1D474C
    bNumConfigurations      1
    Configuration Descriptor:
      bLength                 9
      bDescriptorType         2
      wTotalLength           44
      bNumInterfaces          1
      bConfigurationValue     1
      iConfiguration          0 
      bmAttributes         0x80
        (Bus Powered)
      MaxPower              224mA
      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               3
        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               3
  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   0x00000006
        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   2
        Lowest fully-functional device speed is High Speed (480Mbps)
      bU1DevExitLat          10 micro seconds
      bU2DevExitLat        2047 micro seconds
  Device Status:     0x000c
    (Bus Powered)
    U1 Enabled
    U2 Enabled

  
  Write speed with kernel 4.4:

  $ sudo dd if=/dev/zero of=/dev/sdb bs=1M count=256
  256+0 records in
  256+0 records out
  268435456 bytes (268 MB) copied, 5.98705 s, 44.8 MB/s

  
  Write speed under Mac OS X:

  $ sudo dd if=/dev/zero of=/dev/rdisk2 bs=1048576 count=256
  256+0 records in
  256+0 records out
  268435456 bytes transferred in 0.941998 secs (284963933 bytes/sec)

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