Comment 4 for bug 614351

I am using Acer Aspire Travelmate 290 Series and Ubuntu 10.04. USB worked fine for few days but not any more. When I type lsusb, this is the output:
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

However, when I plug-in any usb flash drive, it is not shown anywhere (I see no way to access it). Though this is what I see as the output of dmesg:
# dmesg | grep USB
[ 2.512617] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
[ 2.513017] ehci_hcd 0000:00:1d.7: new USB bus registered, assigned bus number 1
[ 2.532026] ehci_hcd 0000:00:1d.7: USB 2.0 started, EHCI 1.00
[ 2.532158] hub 1-0:1.0: USB hub found
[ 2.532306] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
[ 2.532329] uhci_hcd: USB Universal Host Controller Interface driver
[ 2.532445] uhci_hcd 0000:00:1d.0: new USB bus registered, assigned bus number 2
[ 2.532597] hub 2-0:1.0: USB hub found
[ 2.532982] uhci_hcd 0000:00:1d.1: new USB bus registered, assigned bus number 3
[ 2.533131] hub 3-0:1.0: USB hub found
[ 2.533323] uhci_hcd 0000:00:1d.2: new USB bus registered, assigned bus number 4
[ 2.533477] hub 4-0:1.0: USB hub found
[ 925.329490] Initializing USB Mass Storage driver...
[ 925.329607] USB Mass Storage support registered.