[Thinlinc-technical] no printing from Windows-client

[Karl Mikaelsson]

Hi Rob,

> 2015-07-19T13:01:10: Printing job with title "My test page" and type
> "application/octet-stream" (1 copies).

Given that the line above doesn't say "application/pdf", the client
assumes that you've configured the thinlocal queue to use "device
dependent mode" (raw), rather than the standard "device independent
mode" (pdf). Device independent mode means that the data is sent "raw"
to the printer - it's up to the print driver on the ThinLinc server to
transform the print job into a data format the printer understands.

These concepts are explained in more depth here:

 https://www.cendio.com/resources/docs/tag/thinlocal.html

Our thinlocal CUPS backend looks at the mime type of the submitted print
jobs to determine if it should send jobs in device dependent or
independent modes. Recently, Red Hat introduced a faulty patch in their
CUPS that ended up breaking our ability to detect the job mime type. To
their credit, they reverted the patch when we informed them, but only
after Ubuntu had managed to copy the same patch into their CUPS package,
and the Ubuntu folks hasn't responded yet to my bug report:

 https://bugs.launchpad.net/ubuntu/+source/cups/+bug/1452193

You can still get prints out of thinlocal even with a broken CUPS, but
it requires that your printer understands PDF files. This leads me to
believe that both of these points are true for your case:

 - You're using an Ubuntu distribution with a broken CUPS
 - Your printer does not accept PDF files directly

As we mention on the platform specific notes page for Ubuntu/Debian:

> A bug in CUPS in Ubuntu forces all print jobs to be marked as raw
> data. This breaks ThinLinc's universal handling of local printers and
> results in PDF data being sent directly to the local printer. Many
> printers can natively handle PDF print jobs and should work despite
> this bug. There is unfortunately no known workaround for other
> printers though.


regards,

-- 
Karl Mikaelsson     derfian at cendio.se
System Developer    +46 (0)13-290863
Cendio AB           https://www.cendio.com/