System hanging, error messages with USB drive on FreeBSD 8.1

Brett Glass brett at
Sun Aug 28 15:21:10 UTC 2011

At 11:43 PM 8/27/2011, Polytropon wrote:
>I'm not sure if this will help you, but I also had similar
>problems with a Kingston USB stick (normal storage stick,
>no removable microSD card). It didn't work on any of my
>FreeBSD systems. So I finally returned it to the shop and
>got a Sony USB stick instead - no problems, works fine.
>So this is my assumption: Some hardware vendors maybe
>improperly implement the USB protocol in their devices,

A Web search reveals that there are dozens which apparently 
have problems with FreeBSD, while Windows has problems with
none of them. This leads me to believe that the problem is 
in FreeBSD, not the hardware.

USB mass storage devices are, for some reason, handled by
FreeBSD's SCSI/CAM subsystem, which seems to want to treat a
USB storage device (a memory stick or a memory card in an
adapter) as a full-out SCSI device when it is not. The
SCSI commands which fail usually have to do with flushing
the cache and/or other functions which just don't apply to
a USB stick. It looks as if the devices which do not have
trouble are just IGNORING the SCSI commands, not executing 
them. In short, FreeBSD really should not be trying to 
issue them in the first place.

In short, this shouldn't be something that's handled by
"quirks." Instead, the system simply should recognize that
a USB memory stick is not a SCSI drive.

--Brett Glass

More information about the freebsd-questions mailing list