[Thinlinc-technical] TL v4.5 : failure printing from Ubuntu-agent (was: Windows-client)

Pierre Ossman ossman at cendio.se
Mon Nov 9 10:37:55 CET 2015

On Sat, 07 Nov 2015 16:20:56 +0100
Rob De Langhe <rob.de.langhe at twistfare.be> wrote:

> The bug description refers to another bug filed at Redhat, bug
> "https://bugzilla.redhat.com/show_bug.cgi?id=1010580"
> In this bug, it is not so clear to me whether there is finally some
> patch, the only 'workaround' I see more or less described as
> succesfull, is setting the printer driver on the client side (I
> assume that, in the context of ThinLinc, that is the agent because
> there the print job is initiated) to "raw" so that the client side is
> not doing any job-content filtering.

There's a lot of technical details on that bug so it's not terribly
easy to follow. The story is basically this:

 - A user could print to his printer locally but not remotely.

 - The bug turned out to be that CUPS is sending the right data, but
   putting an incorrect type label on it. This is only noticeable when
   using an advanced protocol like IPP in combination with having the
   printer driver early in the chain. This is a fairly uncommon setup.

 - Red Hat "fixed" the bug by forcing everything leaving CUPS to be
   tagged as raw data. This is the correct type in most cases when
   sending to a printer. It is not the correct type for advanced queues
   like thinlocal.

 - The "fix" got removed once we pointed out that this was an incorrect
   way of handling things.

 - Users are now experiencing the original bug again, which can be
   worked around by configuring one of the queues as raw.

That's why the workaround does nothing for you. It solves a different

The reason thinlocal doesn't work is because the "fix" is broken. To
get thinlocal working you have to remove that "fix". Red Hat has
already done so, but Ubuntu are still using it.

> -> puzzled as to whom to contact to get this resolved ... As least I
> wanted to share my findings (or lack of...) with anyone here who's
> investigating the same issues on Ubuntu.

It's only Canonical that can fix this properly. They are the ones
compiling the CUPS package for you.

Pierre Ossman           Software Development
Cendio AB		https://cendio.com
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Phone: +46-13-214600	https://plus.google.com/+CendioThinLinc

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

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