CUPS don't detect USB printer

Question

I have 2 usb printers. An old hp deskjet and a new samsung ML-1640.The first works fine with hplip dirver. For the second I have installed the official Samsund driver via AUR.  But CUPS don't see it. It is recognized by the kernel. I see /dev/usb/lp0 device created (root.lp rw-rw---) but still nothing in CUPS .
After searching similar problems on the net I have found a hint that changing permissions on the lp0 device can solve the problem. So chmod +rw lp0 and it WORKS.
But evidently after turn off, turn on of the printer lp0 will have its default permissions again. I tried to find the cause of the problem by comparing the system behavour with my printers. I found that it's identical. The devices are created with the same permissions.
I found also that changing the group of the device to nobody or owner to daemon have the same effect as chmod +rw (it works).
Anybody have an idea why this happen and how to fix it definitively ?
Last edited by artiom (2009-02-10 10:44:43)

Answer 1

Most printers of that class **do need** a slight udev tweak for making them work. Is not wrong to set a +rw on /dev/lp0, but if I were you, I would set a 0660@/dev/lp0 only if it matches your printer.
Maybe something like:
ACTION=="add", SUBSYSTEM=="usb", SYSFS{manofacturer}=="Samsung", MODE="0660", GROUP="lp"
Might help. Obviosly, you need to tweak that rule to your own needs, and **don't forget** to add yourself to the lp group.
Last edited by kjon (2009-02-10 13:08:20)