PATCH: Disable 6 byte commands for USB, firewire, ATAPICAM

John Baldwin jhb at
Wed Jul 30 12:34:38 PDT 2003

On 25-Jul-2003 Nate Lawson wrote:
> Attached is a patch that disables ever sending 6 byte commands to buses
> that do not support them.  Numerous USB devices hang when receiving a 6
> byte command.  For testing, this patch comments out the scsi_da quirks for
> devices that I believe are addressed by this patch and no longer need the
> quirk.
> Please test devices such as USB keys, USB cameras, Firewire hard disks,
> and ATAPICAM cd drives to be sure they still work with this patch.
> Especially if you've needed a quirk before, it is important to see if this
> patch does not break your device.  I hope to get this into the tree early
> so there is plenty of testing before 5.2.

You should remove the 6 to 10 translation that is already in umass(4)
for UFI and ATAPI devices.  I didn't do it for SCSI devices because
the SCSI transport was supposed to work ok with 6 byte commands.  Not
all devices properly report their transport though.


John Baldwin <jhb at>  <><
"Power Users Use the Power to Serve!"  -

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