[Nut-upsdev] directing users towards documentation on udev and permissions

[Charles Lepple]

A lot of recent posts on problems with newhidups, tripplite_usb, etc.
have been related to permission errors, and I don't think the current
error messages really point users in the right direction:

failed to claim USB device, trying 2 more time(s)...
detaching kernel driver from USB device...
failed to detach kernel driver from USB device...
trying again to claim USB device...
failed to claim USB device, trying 1 more time(s)...
detaching kernel driver from USB device...
failed to detach kernel driver from USB device...
trying again to claim USB device...
failed to claim USB device, trying 0 more time(s)...
detaching kernel driver from USB device...
failed to detach kernel driver from USB device...
trying again to claim USB device...
Unable to get HID descriptor (error sending control message: Operation not
permitted)

drivers/libusb.c (trunk, r613), line 233, has the last error message.

We could test for the return code (or errno) being equal to EPERM, but
will that do the wrong thing on *BSD? For that matter, do any of the
BSD USB stacks have restrictive permissions associated with their USB
device nodes?

(We should be OK on OS X, since there seem to be no permission
problems, and libusb's internal darwin_to_errno() can't return EPERM
anyway.)

In any case, if it looks like the problem is related to permissions,
we should mention the hotplug/udev documentation.

Any thoughts on this?

-- 
- Charles Lepple