The udev USB mess on SuSE

The following mail on libusb-devel explains some of the mess regarding the 
/proc to /dev switch for USB device nodes:

http://sourceforge.net/mailarchive/forum.php?thread_id=8008866&forum_id=5425

As far as I get it, generic USB device nodes are to be moved out of the 
/proc and /sys filesystems and get handled by udev instead of hotplug, so 
that part is quite clear.

However for udev to do its work on non-generic devices, it needs the quite 
strange udev rule described in that letter, plus a patch against libusb.

With neither in place, there is no way for udev to lift a device to 
userspace and have it accessible for libusb (which libnjb uses).

So as of today there is no way in hell to get udev to do what hotplug 
does. For that reason it is ill-adviced to remove hotplug from a 
distribution like SuSE have apparently done. My guess is that userspace 
drivers for custom devices that use libusb was way off their map. They 
were thinking of USB devices that support standard classes like CDC ACM, 
USB mass storage flashdrives etc etc. And these work fine, because they 
are handled by the kernel and get their own device nodes from their 
respective kernel modules.

Apparently they left the /proc filesystem backward compatibility stuff in, 
and this is why it works when you run as root. libusb will find the device 
node in /proc and run on it.

You may still be able to use hotplug if you install it by hand 
(possibly you may even need to reconfigure the kernel to enable 
hotplug!), even though SuSE have removed the hotplug RPM from the distro. 
I believe SuSE will notice this sooner or later when they get anger for 
it...

Thats what I figure. Comments?

Linus

PS: if you have a mail address for someone USB-minded inside SuSE/Novell, 
please forward this letter to that address.


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