Re: lsusb: Get "unable to initialize libusb: -99".

[Alan M. <ac...@mu...>]

>Alan Mackenzie wrote:
>> , I get the following response:
>> 
>>     unable to initialize libusb: -99

>This is LIBUSB_ERROR_OTHER so it would be helpful if you could
>provide a complete log from libusb.git built with debugging enabled.
>(This is the default when running autogen.sh && make)

OK.  That'll take me a little time.

>> Relevant: My /dev directory is managed by busybox's mdev, not the more
>> usual udev.  On a udev system which is otherwise "the same", lsusb
>> works fine.

>So what device nodes does mdev create and why isn't it compatible
>with udev in this regard?

/dev/usbmon[0-7], with these major/minor numbers:
crw-rw---- 1 root root 251, 0 Apr 22 20:25 /dev/usbmon0

I can't see any other usb'ish looking devices in /dev.

>The Linux backend for libusb currently looks in /dev/bus/usb or in
>sysfs. http://libusb.org/ticket/119 has a patch that adds additional
>checks for /dev/usbdev* which might help also with mdev?

mdev doesn't create /dev/usb.  I can't get my head round /sys, it's just
too complicated.  The patch looks like it could be adapted to handle
/dev/usbmon[0-7] instead, or as well.

//Peter

-- 
Alan Mackenzie (Nuremberg, Germany).