libusb usb_open(when using desc) broken?

Steve Franks stevefranks at
Mon May 12 19:10:29 UTC 2008


I've observed that several different projects which use libusb to talk
to hardware are "broken" when built on freebsd - they fail on opening
the device.  If I corrupt them to open on just a vid+pid (as opposed
to vid+pid+desc), they work fine.  Is it possible that FreeBSD is
handling usb "description" strings (alot of doc's are really unclear
on just what "desc" is, exactly - I've heard serial number, name,
content from dmesg, etc) differently than linux - because all these
projects are linux-based, and the linux users are always confounded
when I describe the problem to them.  One of the projects is
"openocd", which uses libusb through libftdi, and the other is
"urjtag" which I assume uses it natively, since it's not ftdi-based
hardware.  I'm about to start digging around in the urjtag source
today, previously I assumed it was a libftdi problem until it happened
a second time.


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