I'm running Debian (sid, custom compiled Debian kernel version 2.6.14) on an IBM Thinkpad R50, and have been having trouble getting an AMS Venus DS-2316SU2BK enclosure working. Here's a paste from /var/log/messages that indicates the basic error:

kernel: usb 4-4: new high speed USB device using ehci_hcd and address 22
kernel: scsi20 : SCSI emulation for USB Mass Storage devices
kernel: Vendor: ST325082 Model: 3AS Rev: 3.03
kernel: Type: Direct-Access ANSI SCSI revision: 04
kernel: SCSI device sda: 488397168 512-byte hdwr sectors (250059 MB)
kernel: SCSI device sda: 488397168 512-byte hdwr sectors (250059 MB)
kernel: sda:<7>usb-storage: queuecommand called
kernel: sda1 sda2
kernel: Attached scsi disk sda at scsi20, channel 0, id 0, lun 0
kernel: usb 4-4: USB disconnect, address 22
kernel: sd 20:0:0:0: SCSI error: return code = 0x10000
kernel: end_request: I/O error, dev sda, sector 488396928
kernel: printk: 8 messages suppressed.

The hard drive (Seagate Barracuda ST3250823AS) has been set up in XP with a 100GB NTFS partition, a 32GB FAT-32 partion, and the remainder not partitioned.

Things I have tried which have not solved the problem:
* compiled in usb-storage vs. module
* changing max_sectors in drivers/usb/storage/scsiglue.c to a lower number
(by commenting out if statement relating to USB_VENDOR_ID_GENESYS)
* different HDD (previously Hitachi Deskstar T7K250)
* different USB cable (cable that came with the enclosure, and another Hi-Speed cable I had lying around at home)
* previous kernel (2.6.12)

I see a few lines near the end of the debug output that look suspicious, particularly the one saying "Invalid command operation code":

Bulk status result = 0
Bulk Status S 0x53425355 T 0x8 R 0 Stat 0x0
-- Result from auto-sense is 0
-- code: 0x70, key: 0x5, ASC: 0x20, ASCQ: 0x0
Illegal Request: Invalid command operation code
scsi cmd done, result=0x2

I'll put the full debug output from one connect/disconnect cycle in a subsequent post.

lsmod is as follows:

Module Size Used by
ehci_hcd 37064 0
usb_storage 81072 16
radeon 110144 1
ntfs 109424 0
irtty_sir 9088 2
sir_dev 19500 1 irtty_sir
uhci_hcd 34320 0
piix 10692 0 [permanent]
usbcore 127616 4 ehci_hcd,usb_storage,uhci_hcd
irda 207804 2 irtty_sir,sir_dev

lspci:

0000:00:00.0 Host bridge: Intel Corporation 82855PM Processor to I/O Controller (rev 03)
0000:00:01.0 PCI bridge: Intel Corporation 82855PM Processor to AGP Controller (rev 03)
0000:00:1d.0 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #1 (rev 01)
0000:00:1d.1 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #2 (rev 01)
0000:00:1d.2 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #3 (rev 01)
0000:00:1d.7 USB Controller: Intel Corporation 82801DB/DBM (ICH4/ICH4-M) USB2 EHCI Controller (rev 01)
0000:00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev 81)
0000:00:1f.0 ISA bridge: Intel Corporation 82801DBM (ICH4-M) LPC Interface Bridge (rev 01)
0000:00:1f.1 IDE interface: Intel Corporation 82801DBM (ICH4-M) IDE Controller (rev 01)
0000:00:1f.3 SMBus: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) SMBus Controller (rev 01)
0000:00:1f.5 Multimedia audio controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Audio Controller (rev 01)
0000:00:1f.6 Modem: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Modem Controller (rev 01)
0000:01:00.0 VGA compatible controller: ATI Technologies Inc Radeon Mobility M7 LW [Radeon Mobility 7500]
0000:02:00.0 CardBus bridge: Texas Instruments PCI4520 PC card Cardbus Controller (rev 01)
0000:02:00.2 FireWire (IEEE 1394): Texas Instruments: Unknown device 802a (rev 01)
0000:02:01.0 Ethernet controller: Intel Corporation 82540EP Gigabit Ethernet Controller (Mobile) (rev 03)
0000:02:02.0 Ethernet controller: Atheros Communications, Inc. AR5212 802.11abg NIC (rev 01)

As mentioned, here's the usb_storage debug output:

kernel: usb-storage:
USB Mass Storage device detected
-- associate_dev
Vendor: 0x0928, Product: 0x0002, Revision: 0x0000
Interface Subclass: 0x06, Protocol: 0x50
Transport: Bulk
Protocol: Transparent SCSI
usb_stor_control_msg: rq=fe rqtype=a1 value=0000 index=00 len=1
GetMaxLUN command result is 1, data is 0
*** thread sleeping.
device found at 22
waiting for device to settle before scanning
queuecommand called
*** thread awakened.
Command INQUIRY (6 bytes)
12 00 00 00 24 00
Bulk Command S 0x43425355 T 0x1 L 36 F 128 Trg 0 LUN 0 CL 6
usb_stor_bulk_transfer_buf: xfer 31 bytes
Status code 0; transferred 31/31
-- transfer complete
Bulk command transfer result=0
usb_stor_bulk_transfer_sglist: xfer 36 bytes, 1 entries
Status code 0; transferred 36/36
-- transfer complete
Bulk data transfer result 0x0
Attempting to get CSW...
usb_stor_bulk_transfer_buf: xfer 13 bytes
Status code 0; transferred 13/13
-- transfer complete
Bulk status result = 0
Bulk Status S 0x53425355 T 0x1 R 0 Stat 0x0
scsi cmd done, result=0x0
*** thread sleeping.
queuecommand called
*** thread awakened.
Command TEST_UNIT_READY (6 bytes)
00 00 00 00 00 00
Bulk Command S 0x43425355 T 0x2 L 0 F 0 Trg 0 LUN 0 CL 6
usb_stor_bulk_transfer_buf: xfer 31 bytes
Status code 0; transferred 31/31
-- transfer complete
Bulk command transfer result=0
Attempting to get CSW...
usb_stor_bulk_transfer_buf: xfer 13 bytes
Status code 0; transferred 13/13
-- transfer complete
Bulk status result = 0Bulk Status S 0x53425355 T 0x2 R 0 Stat 0x0
scsi cmd done, result=0x0
*** thread sleeping.
queuecommand called
*** thread awakened.
Command READ_CAPACITY (10 bytes)
25 00 00 00 00 00 00 00 00 00
Bulk Command S 0x43425355 T 0x3 L 8 F 128 Trg 0 LUN 0 CL 10
usb_stor_bulk_transfer_buf: xfer 31 bytes
Status code 0; transferred 31/31
-- transfer complete
Bulk command transfer result=0
usb_stor_bulk_transfer_sglist: xfer 8 bytes, 1 entries
Status code 0; transferred 8/8
-- transfer complete
Bulk data transfer result 0x0
Attempting to get CSW...
usb_stor_bulk_transfer_buf: xfer 13 bytes
Status code 0; transferred 13/13
-- transfer complete
Bulk status result = 0
Bulk Status S 0x53425355 T 0x3 R 0 Stat 0x0
scsi cmd done, result=0x0
*** thread sleeping.
queuecommand called
*** thread awakened.
Command TEST_UNIT_READY (6 bytes)
00 00 00 00 00 00
Bulk Command S 0x43425355 T 0x4 L 0 F 0 Trg 0 LUN 0 CL 6
usb_stor_bulk_transfer_buf: xfer 31 bytes
Status code 0; transferred 31/31
-- transfer complete
Bulk command transfer result=0
Attempting to get CSW...
usb_stor_bulk_transfer_buf: xfer 13 bytes
Status code 0; transferred 13/13
-- transfer complete
Bulk status result = 0
Bulk Status S 0x53425355 T 0x4 R 0 Stat 0x0
scsi cmd done, result=0x0
*** thread sleeping.
queuecommand called
*** thread awakened.
Command READ_CAPACITY (10 bytes)
25 00 00 00 00 00 00 00 00 00
Bulk Command S 0x43425355 T 0x5 L 8 F 128 Trg 0 LUN 0 CL 10
usb_stor_bulk_transfer_buf: xfer 31 bytes
Status code 0; transferred 31/31
-- transfer complete
Bulk command transfer result=0
usb_stor_bulk_transfer_sglist: xfer 8 bytes, 1 entries
Status code 0; transferred 8/8
-- transfer complete
Bulk data transfer result 0x0
Attempting to get CSW...
usb_stor_bulk_transfer_buf: xfer 13 bytes
Status code 0; transferred 13/13
-- transfer complete
Bulk status result = 0
Bulk Status S 0x53425355 T 0x5 R 0 Stat 0x0
scsi cmd done, result=0x0
*** thread sleeping.
*** thread awakened.
Command READ_10 (10 bytes)
28 00 00 00 00 00 00 00 08 00
Bulk Command S 0x43425355 T 0x6 L 4096 F 128 Trg 0 LUN 0 CL 10
usb_stor_bulk_transfer_buf: xfer 31 bytes
Status code 0; transferred 31/31
-- transfer complete
Bulk command transfer result=0
usb_stor_bulk_transfer_sglist: xfer 4096 bytes, 1 entries
Status code 0; transferred 4096/4096
-- transfer complete
Bulk data transfer result 0x0
Attempting to get CSW...
usb_stor_bulk_transfer_buf: xfer 13 bytes
Status code 0; transferred 13/13
-- transfer complete
Bulk status result = 0
Bulk Status S 0x53425355 T 0x6 R 0 Stat 0x0
scsi cmd done, result=0x0
*** thread sleeping.
queuecommand called
*** thread awakened.
Command (unknown command) (12 bytes)
a0 00 00 00 00 00 00 00 10 00 00 00
Bulk Command S 0x43425355 T 0x7 L 4096 F 128 Trg 0 LUN 0 CL 12
usb_stor_bulk_transfer_buf: xfer 31 bytes
Status code 0; transferred 31/31
-- transfer complete
Bulk command transfer result=0
usb_stor_bulk_transfer_sglist: xfer 4096 bytes, 1 entries
Status code -32; transferred 0/4096
clearing endpoint halt for pipe 0xc0009680
usb_stor_control_msg: rq=01 rqtype=02 value=0000 index=81 len=0
usb_stor_clear_halt: result = 0
Bulk data transfer result 0x2
Attempting to get CSW...
usb_stor_bulk_transfer_buf: xfer 13 bytes
Status code 0; transferred 13/13
-- transfer complete
Bulk status result = 0
Bulk Status S 0x53425355 T 0x7 R 4096 Stat 0x1
-- transport indicates command failure
-- unexpectedly short transfer
Issuing auto-REQUEST_SENSE
Bulk Command S 0x43425355 T 0x8 L 18 F 128 Trg 0 LUN 0 CL 6
usb_stor_bulk_transfer_buf: xfer 31 bytes
Status code 0; transferred 31/31
-- transfer complete
Bulk command transfer result=0
usb_stor_bulk_transfer_buf: xfer 18 bytes
Status code 0; transferred 18/18
-- transfer complete
Bulk data transfer result 0x0
Attempting to get CSW...
usb_stor_bulk_transfer_buf: xfer 13 bytes
Status code 0; transferred 13/13
-- transfer complete
Bulk status result = 0
Bulk Status S 0x53425355 T 0x8 R 0 Stat 0x0
-- Result from auto-sense is 0
-- code: 0x70, key: 0x5, ASC: 0x20, ASCQ: 0x0
Illegal Request: Invalid command operation code
scsi cmd done, result=0x2
*** thread sleeping.

# this next bit is repeated 7 times, with the number
# in Bad target number the only thing changing (1-7)
queuecommand called
*** thread awakened.
Bad target number (1:0)
scsi cmd done, result=0x40000
*** thread sleeping.

device scan complete
queuecommand called
*** thread awakened.
Command READ_10 (10 bytes)
28 00 1d 1c 58 80 00 00 08 00
Bulk Command S 0x43425355 T 0x9 L 4096 F 128 Trg 0 LUN 0 CL 10
usb_stor_bulk_transfer_buf: xfer 31 bytes
Status code 0; transferred 31/31
-- transfer complete
Bulk command transfer result=0
usb_stor_bulk_transfer_sglist: xfer 4096 bytes, 1 entries
Status code 0; transferred 4096/4096
-- transfer complete
Bulk data transfer result 0x0
Attempting to get CSW...
usb_stor_bulk_transfer_buf: xfer 13 bytes
Status code -71; transferred 0/13
-- unknown error
Bulk status result = 4
-- transport indicates error, resetting
storage_disconnect() called
usb_stor_stop_transport called
usb_reset_device returns -19
usb_stor_Bulk_reset called
No reset during disconnect
scsi cmd done, result=0x70000
queuecommand called
Fail command during disconnect
-- usb_stor_release_resources
-- sending exit command to thread
-- dissociate_dev
*** thread sleeping.
*** thread awakened.
-- exiting

For what it's worth, I think I've tracked down the segment of code that is producing the "Illegal Request: Invalid command operation code" error message (drivers/scsi/sr_ioctl.c, line ~149):

Not sure if this helps, but it does seem like the SCSI code as well as the USB code is involved here...

Okay, I found a solution that seems to work so far (in that I can now access my FAT32 partition under Linux), using rough instructions from the following address:

http://64.62.136.189/linux-scsi@vger.../msg01260.html

According to that post, the error is related to the unknown command 0xA0...10..., which sends a REPORT_LUNS signal to the enclosure, resulting in badness. This is apparently because the device reports to be SCSI revision 04, but does not support all the commands. The solution is to stop the driver sending REPORT_LUNS to the enclosure. In my case, I did the following:
The generic solution (according to the last post by Patrick Mansfield on that thread) is the following, assuming that scsi_mod has been loaded (or compiled in):
Where <vendor> and <model> are taken from the kernel messages when the device is plugged in. In my case:

Hello gringer,

This also may happen with the Laser SATA/USB2 external HDD case, at least for Linux kernel version 2.6.18. The behavior is a bit different, because I can write files to the drive (including a 12GB image), but it fails most of the time for writing lots of little files to the disk.

/var/log/messages output (showing vendor, model):

"fix" script:

This has not been tested extensively yet, so I'm not really sure if it will work. On the other hand, I have now been able to finish some music tagging, which I was not able to complete before now (without the disk failing part way through).