Hello, On Feb 24 21:55 Pit Suetterlin wrote:
I just bought a new printer, a Samsung ML-2851ND. Thought "OK, let's install that thing". Just out of curiosity I watched /var/log/messages when I connected it (it has network, but I'm using USB at the moment). What do I see?
Feb 24 21:27:01 snoopy udev-configure-printer: URI matches without serial number: usb://Samsung/ML-2850%20Series Feb 24 21:27:01 snoopy udev-configure-printer: No serial number URI matches so using those without Feb 24 21:27:01 snoopy udev-configure-printer: About to add queue for usb://Samsung/ML-2850%20Series Feb 24 21:27:01 snoopy udev-add-printer: add_queue: URIs=['usb://Samsung/ML-2850%20Series'] Feb 24 21:27:01 snoopy udev-add-printer: D-Bus method call failed: org.freedesktop.DBus.Error.ServiceUnknown: The name com.redhat.NewPrinterNotification was not provided by any .service files Feb 24 21:27:11 snoopy udev-add-printer: PPD: Samsung/ML-2850D-Postscript.ppd.gz; Status: 0
Uh. Ok, lets see: snoopy:~% lpq ML-2850-Series is ready no entries
Wow. No, WOW! I knew it's a PostScript printer and expected little work. But that was an absolute zero-conf thing. Just plug it in and print. As I said - I'm *really* impressed....
Nothing else but pure luck ;-) See the details below. By the way: Does it even actually print correctly? It is not really a big problem to implement an automated print queue setup which uses whatever random driver. The crucial point regarding any kind of print queue setup is how to automatically determine an appropriate driver according to the model strings which whatever autodetected printer device out there in the wild reports via USB. There is no such thing as authoritative lists where USB IDs for USB printers are mapped to appropriate driver descriptions (i.e. PPD files). Of course the printer manufacturers could provide this data but they just insist not to do it, compare http://en.opensuse.org/SDB:Information_for_Printer_Manufacturers_Regarding_L... Therefore each print queue setup tool implements its own kind of best-effort/best-guess magic to automatically determine appropriate drivers (actually PPD files) according to the model strings which an autodetected printer device reports. Therefore it is crucial that whatever "smart" automated printer setup tool does not set up print queues with blind guessed drivers. Instead any automated printer setup tool must give up whenever something looks fishy while it tries to find an appropriate driver. In your particular case the device reports to be a "Samsung ML-2850 Series" and udev-configure-printer determines that Samsung/ML-2850D-Postscript.ppd.gz is an appropriate driver description file but this is only a best-effort/best-guess attempt. Of course all those best-effort/best-guess attempts work well in very most cases where "works well" also means when a printer setup tool just gives up because something looks fishy while it tries to find an appropriate driver. Nevertheless from a strict theoretical point of view, when an automated queue setup is actually successful, it is nothing else but pure luck. Kind Regards Johannes Meixner -- SUSE LINUX Products GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany AG Nuernberg, HRB 16746, GF: Markus Rex -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org