Comment # 133 on bug 920937 from Ian Powell

(In reply to Johannes Meixner from comment #132)
> FYI regarding the issue that
> running plain /usr/lib/cups/backend/usb as root shows a USB printer
> but "lpinfo -v" and the CUPS web frontend and other printer setup tools
> do not show it:
> 
> It seems bug#938659 shows the root cause:
> "udev does not set 'rw-rw-r-- root lp' for device node for all USB printers"
> see in particular
> https://bugzilla.suse.com/show_bug.cgi?id=938659#c4
> 
> Perhaps it works for Ian Powell because he got a newer udev
> but I am not at all a sufficient udev expert to really know.

It all still works happily. 
my current udev info as per rpm -qa | grep udev - not sure what it was when
things didn't work.
libgudev-1_0-0-219-6.2.x86_64
udev-browse-0.3-9.2.x86_64
libinput-udev-0.18-1.1.x86_64
libudev1-219-6.2.x86_64
udev-219-6.2.x86_64
python-pyudev-0.16.1-10.3.noarch
udev-configure-printer-1.5.7-2.1.x86_64

udev also set "crw-rw- r--+ root lp" for my scanner as well

bus/usb/001:
crw-rw-r--  1 root root 189, 0 Jul 21 08:20 001
crw-rw-r--+ 1 root lp   189, 1 Jul 21 08:20 002
crw-rw-r--+ 1 root lp   189, 4 Jul 21 13:08 005