My pen Drive was working before, after i updated the Ubuntu Version 12.04, USB hot plug never worked. But i verified in Windows PC, it was working. please help me to resolve this problem.
dmesg output
[22677.764094] usb 2-1: device not accepting address 22, error -71
[22677.820308] hub 2-0:1.0: unable to enumerate USB device on port 1
[22678.640088] usb 2-1: new high-speed USB device number 24 using ehci_hcd
[22678.775370] scsi9 : usb-storage 2-1:1.0
[22679.772889] scsi 9:0:0:0: Direct-Access MBIL-SSM KNIGHT 0100 PQ: 0 ANSI: 2
[22679.773492] scsi 9:0:0:1: CD-ROM MBIL-SSM KNIGHT 0100 PQ: 0 ANSI: 2
[22679.774692] sd 9:0:0:0: Attached scsi generic sg2 type 0
[22679.778091] sd 9:0:0:0: [sdb] 7831552 512-byte logical blocks: (4.00 GB/3.73 GiB)
[22679.778982] sr1: scsi3-mmc drive: 8x/40x writer xa/form2 cdda tray
[22679.779287] sr 9:0:0:1: Attached scsi CD-ROM sr1
[22679.779453] sr 9:0:0:1: Attached scsi generic sg3 type 5
[22679.779587] sd 9:0:0:0: [sdb] Write Protect is off
[22679.779594] sd 9:0:0:0: [sdb] Mode Sense: 23 00 00 00
[22679.780777] sd 9:0:0:0: [sdb] No Caching mode page present
[22679.780785] sd 9:0:0:0: [sdb] Assuming drive cache: write through
[22679.786296] sd 9:0:0:0: [sdb] No Caching mode page present
[22679.786302] sd 9:0:0:0: [sdb] Assuming drive cache: write through
[22680.766665] sdb: sdb1
[22680.770703] sd 9:0:0:0: [sdb] No Caching mode page present
[22680.770709] sd 9:0:0:0: [sdb] Assuming drive cache: write through
[22680.770713] sd 9:0:0:0: [sdb] Attached SCSI removable disk
[22680.904065] usb 2-1: reset high-speed USB device number 24 using ehci_hcd
