Comment 3 for bug 90724

I had the same problem with my Samsung ML-1520 usb printer after updating.

I think I found the reason for this problem.
Here is my analysis:

The backported libgphoto2 package installs a new udev rule file. Where previously SYSFS{...} was used to match against attributes now ATTRS{...} is employed.
This is a syntax which the udev version in egdy does not recognize. My guess here (as I do not have feisty installed ) is that feisty is using a newer udev version. The udev man page under edgy does not mention any ATTRS for its syntax in rule files.

This wrong syntax now causes udev to create a device file with the wrong ownership set, specifically group ownership of plugdev. This seems to be true for any plugged in device, whose vendorid happens to be preset in the libgphoto rule file. For pinters this leads to a device entry /dev/usblpxx with group ownership set to plugdev.

Since the cups system operates in group lp cups is no longer able to acces the printer device, hence no printing is possible.

Since it is sufficient, that only the vendorid has to have a match in the libgphoto rule file, this problem should affect any usb printer whose vendor also sells cameras, which is true for a lot of brands (canon, hp, epson, minolta, samsung ...). So this should be a widely spread problem. A look at recent posts in the ubuntu forums confirms this assumption.

Essentially the backport update rendered the printing system unusable.

I was able to workaround this problem by replacing all occurances of ATTRS with SYSFS in the libgphoto rule file.

hth
cheers
martin