Odd USB problem on THOMSON PDP95FM

["Marco Ferra" <mferra@gmail.com>]

Hi kernel developers

I don't know if this is the proper list but I have a very odd problem
and it's driving me nuts for the past two days.

I have a portable mp3 player named:

usb-storage: waiting for device to settle before scanning
  Vendor: THOMSON   Model: PDP95FM Series    Rev: 0100
  Type:   Direct-Access                      ANSI SCSI revision: 04
usb-storage: device scan complete
SCSI device sda: 244288 2048-byte hdwr sectors (500 MB)
sda: Write Protect is off
sda: Mode Sense: 3e 00 00 00
sda: assuming drive cache: write through
SCSI device sda: 244288 2048-byte hdwr sectors (500 MB)
sda: Write Protect is off
sda: Mode Sense: 3e 00 00 00
sda: assuming drive cache: write through
 sda: unknown partition table
sd 0:0:0:0: Attached scsi removable disk sda

that, I think, should act like an USB mass storage disk.  I have done:

# dd if=/dev/sda of=/dev/sda.dump

sucessfully, several times.  But I can't do:

# dd if=/dev/zero of=/dev/sda

The error, all the time:

usb 2-1: reset full speed USB device using uhci_hcd and address 3
usb 2-1: reset full speed USB device using uhci_hcd and address 3
usb 2-1: reset full speed USB device using uhci_hcd and address 3
usb 2-1: reset full speed USB device using uhci_hcd and address 3
usb 2-1: reset full speed USB device using uhci_hcd and address 3
usb 2-1: reset full speed USB device using uhci_hcd and address 3
sd 0:0:0:0: SCSI error: return code = 0x50000
end_request: I/O error, dev sda, sector 1064
Buffer I/O error on device sda, logical block 133
lost page write due to I/O error on sda

and from dd:

bash-3.00# dd if=/dev/zero of=/dev/sda
dd: writing to `/dev/sda': Input/output error
13489+0 records in
13488+0 records out
6905856 bytes (6.9 MB) copied, 206.473 seconds, 33.4 kB/s
dd: closing input file `/dev/zero': Bad file descriptor

It never stops on the same place, but is always before reaching the
7 MB.  I thought that I could ajust some tuneable parameters here:

/sys/block/sda/device

But I'm completly lost on the problem.  If anyone could be of assistance,
it would appreciated.

Sincere regards
Marco