I wonder if there should be a mask in the minor number to indicate
alternative exclusivity semantics.  The exclusive open is almost
certainly there because a number of USB-using programs expect that
once a device is opened no other program will access it.

Alternatively, GNU Radio could be modified to only open the control
endpoint in one place.  But if Linux allows multiple opens, then we
probably need to at least optionally do that - it doesn't seem
intrinsically crazy and it seems easier to allow multiple opens than
fight it.

-- 
        Greg Troxel <gdt@ir.bbn.com>