[cups] Arch Linux, networked Brother j625dw "Unable to locate printer"

[Johannes Meixner]

Hello,

On Jun 23 17:03 Aaron Laws wrote (excerpt):
> ... this printer works on other machines just fine over network

First and foremost verify that it still works via USB
on the machine where it does not work over network.

Then get CUPS debug messages for one single print job
on the machines where it works and compare them with the
CUPS debug messages on the machine where it does not work
and try to find those differences that seem to indicate
what the root cause could be.

Unfortunately in particular proprietary third-party driver
software often does not emit useful debug messages.
(I guess "proprietary" => "secretive" => "silence" ;-)
When the root cause is inside Brother's driver software
you may not see why it fails in your CUPS debug messages.

Sometimes proprietary third-party driver software does
no longer work on systems with a newer version of the
base printing system e.g. newer CUPS version and/or
newer version of other components of the base printing
system (like newer printing filters and so on), cf.
"Printers with non-free driver software" at
https://en.opensuse.org/SDB:Printer_buying_guide

In general since CUPS 1.6 several base printing filters
were moved out of CUPS into the separated "cups-filters"
software that is provided by the OpenPrinting workgroup
of the Linux Foundation and additionally the standard
print job data format was changed from PostScript to PDF, cf
http://www.linuxfoundation.org/collaborate/workgroups/openprinting/pdf_as_standard_print_job_format
and
https://en.opensuse.org/Concepts_printing

The new PDF printing workflow is reasonably backward-compatible
with PostScript (printing PostScript files usually works
as before).

But if a proprietary third-party driver software somehow
only works with the traditional PostScript workflow,
it will no longer work with the new PDF workflow.


FYI:

Regarding CUPS debug messages:
Anything a printing filter (printer drivers are filters)
or a CUPS backend emits to stderr becomes a CUPS debug message
because the stderr output of filters and backends is forwarded
to /var/log/cups/error_log if there is "LogLevel debug" set
in /etc/cups/cupsd.conf.

Regarding printing filters and backends in general see
"The Filter (includes the Driver)" and "The Backends" at
https://en.opensuse.org/SDB:CUPS_in_a_Nutshell


Kind Regards
Johannes Meixner
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Dilip Upmanyu, Graham Norton - HRB 21284 (AG Nuernberg)