I recently upgraded to Ubuntu 14.04 and now my flash drive don't even blink when plugged in! I tested the flash drive on windows PC and it works fin. Tester the usb port on same PC on linux mint (dual boot) it works fin.

lsblk command shows:

NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT

sda      8:0    0 465.8G  0 disk 

├─sda1   8:1    0     1K  0 part 

├─sda4   8:4    0 147.5G  0 part 

├─sda5   8:5    0   976M  0 part [SWAP]

├─sda6   8:6    0 158.7G  0 part /

└─sda7   8:7    0 158.7G  0 part /home

sr0     11:0    1  1024M  0 rom  

when disconnecting and reconnecting the USB flash drive dmesg command shows:

[132068.186064] usb 3-1: USB disconnect, device number 21

[132070.613840] usb 3-1: new high-speed USB device number 22 using xhci_hcd

[132070.634747] usb 3-1: New USB device found, idVendor=0718, idProduct=063d

[132070.634759] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3

[132070.634766] usb 3-1: Product: Nano Pro

[132070.634771] usb 3-1: Manufacturer: Imation

[132070.634776] usb 3-1: SerialNumber: 07B20C039F1207BB

[132070.635151] xhci_hcd 0000:00:14.0: Not enough bandwidth. Proposed: 2032098, Max: 1607

[132070.635164] xhci_hcd 0000:00:14.0: Not enough bandwidth

[132070.635180] usb 3-1: can't set config #1, error -12

tail /var/log/syslog before usb plugin:

Jun 26 11:33:41 waqleh-Inspiron-3521 NetworkManager[1138]: message repeated 6 times: [ <warn> nl_recvmsgs() error: (-33) Dump inconsistency detected, interrupted]

Jun 26 11:35:09 waqleh-Inspiron-3521 NetworkManager[1138]: <info> (eth1): device state change: unavailable -> unmanaged (reason 'removed') [20 10 36]

Jun 26 11:35:09 waqleh-Inspiron-3521 NetworkManager[1138]: <info> (eth1): cleaning up...

Jun 26 11:35:09 waqleh-Inspiron-3521 NetworkManager[1138]: <warn> (5) failed to find interface name for index

Jun 26 11:35:09 waqleh-Inspiron-3521 NetworkManager[1138]: (nm-system.c:766):nm_system_iface_get_flags: runtime check failed: (iface != NULL)

Jun 26 11:35:09 waqleh-Inspiron-3521 NetworkManager[1138]: <error> [1403771709.565624] [nm-system.c:768] nm_system_iface_get_flags(): (unknown): failed to get interface link object

Jun 26 11:35:09 waqleh-Inspiron-3521 kernel: [80331.126126] ipheth 3-1:4.2: Apple iPhone USB Ethernet now disconnected

Jun 26 11:35:09 waqleh-Inspiron-3521 avahi-daemon[964]: Withdrawing workstation service for eth1.

Jun 26 11:35:09 waqleh-Inspiron-3521 NetworkManager[1138]:    SCPlugin-Ifupdown: devices removed (path: /sys/devices/pci0000:00/0000:00:14.0/usb3/3-1/3-1:4.2/net/eth1, iface: eth1)

Jun 26 11:35:10 waqleh-Inspiron-3521 kernel: [80332.034212] usb 3-2: USB disconnect, device number 5

tail /var/log/syslog after usb plugin:

waqleh@waqleh-Inspiron-3521:/$ tail /var/log/syslog

Jun 26 11:35:09 waqleh-Inspiron-3521 NetworkManager[1138]:    SCPlugin-Ifupdown: devices removed (path: /sys/devices/pci0000:00/0000:00:14.0/usb3/3-1/3-1:4.2/net/eth1, iface: eth1)

Jun 26 11:35:10 waqleh-Inspiron-3521 kernel: [80332.034212] usb 3-2: USB disconnect, device number 5

Jun 26 11:35:38 waqleh-Inspiron-3521 kernel: [80359.920678] usb 3-4: new high-speed USB device number 7 using xhci_hcd

Jun 26 11:35:38 waqleh-Inspiron-3521 kernel: [80359.941686] usb 3-4: New USB device found, idVendor=0718, idProduct=063d

Jun 26 11:35:38 waqleh-Inspiron-3521 kernel: [80359.941698] usb 3-4: New USB device strings: Mfr=1, Product=2, SerialNumber=3

Jun 26 11:35:38 waqleh-Inspiron-3521 kernel: [80359.941704] usb 3-4: Product: Nano Pro

Jun 26 11:35:38 waqleh-Inspiron-3521 kernel: [80359.941709] usb 3-4: Manufacturer: Imation

Jun 26 11:35:38 waqleh-Inspiron-3521 kernel: [80359.941714] usb 3-4: SerialNumber: 07B20C039F1207BB

Jun 26 11:35:38 waqleh-Inspiron-3521 mtp-probe: checking bus 3, device 7: "/sys/devices/pci0000:00/0000:00:14.0/usb3/3-4"

Jun 26 11:35:38 waqleh-Inspiron-3521 mtp-probe: bus: 3, device: 7 was not an MTP device

I have a DELL - Inspiron 15-3521

uname -a command shows:

Linux waqleh-Inspiron-3521 3.13.0-29-generic #53-Ubuntu SMP Wed Jun 4
21:02:19 UTC 2014 i686 i686 i686 GNU/Linux

I even updated the BIOS to latest
sudo dmidecode -s bios-version:
A12