[cups-devel] [UNKN] STR #4734: Ubuntu 14 LTS Cups will not print to local printer

[Johannes Meixner]

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[STR Unresolved]

Only FYI a possible workaround:

When "echo /path/to/raw/doc >/dev/usb/lp1" works
you could use a selfmade backend that implememts
this way of sending data to the printer device, see
"A careless backend for a single USB printer" at
https://en.opensuse.org/SDB:Using_Your_Own_Backends_to_Print_with_CUPS

Because in your case it is /dev/usb/lp1 it seems
you have two USB printers connected (one at /dev/usb/lp0
and the other one at /dev/usb/lp1).
In this case a careless backend that sends data
hardcoded to /dev/usb/lp1 could lead to problems
because there is no guarantee what printer device
will become /dev/usb/lp0 versus /dev/usb/lp1
so that a careless backend could sent its data
to the wrong printer device.
To avoid that you need to implement printer device detection
in your backend so that your backend sends its data to the
USB device node that matches the intended printer device.

Only a blind guess regarding the root cause
why CUPS cannot send data to your USB printer device:
Since some time the 'usb' backend in CUPS does no longer
use the kernel USB driver "usblp" but instead it uses "libusb".
Perhaps the libusb-based CUPS backend 'usb' cannot detect your
printer device (see what /usr/lib/cups/backend/usb reports)
and when it cannot detect it, it cannot send data to it
or something else fails via libusb.

Furthermore you may have a look at the
  Debugging "Unable to send data to printer."
mail thread on Sep 2015 at cups at cups.org
http://cups.org/pipermail/cups/2015-September/thread.html

Link: https://www.cups.org/str.php?L4734
Version: 1.7.2
Fix Version: Third-party
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