[cups.general] "Open print channel failed"

[Johannes Meixner]

Hello,

On Jul 17 08:58 Paul van der Vlis wrote (shortened):
> After update of Debian from 3.1 to 4.0 I have a printer problem at a
> customer. Cups says: "open print channel failed; will retry in 30
> seconds...". My customer has an HP laserjet 2300d, connected with USB.
> They are using HPlip. In syslog I see: "hpiod: invalid MLCInitReply".

This is no CUPS problem.

hpiod belongs to the HPLIP software, see
http://hplip.sourceforge.net/
in particular
http://hplip.sourceforge.net/mailing_lists.html
where the developers at HP do a great job to help users.

Perhaps it is a HPLIP problem but I guess it is a USB problem.


> What will be wrong, is this a hardware problem?

There was a similar problem on hplip-help at lists.sourceforge.net
and in the end it was a hardware problem.
The user exchanged his USB cable and then it works.
Preferably use a short USB cable and connect the printer at least
for a test directly (i.e. without USB hubs) to the computer.


> hp:/usb/hp_LaserJet_2300_series?serial=CNCGK07727

By the way:
Plain printing should work regardless which backend is used.
In particular I mean
http://hplip.sourceforge.net/tech_docs/hpijs.html
--------------------------------------------------------------------
HPIJS provides no I/O. HPIJS emits standard file output. The output
can be directed to a file or to the actual device via the parallel
or USB port. This "raw" printing does not require bi-directional I/O.
Some all-in-one devices do not support "raw" I/O and must use HPLIP
for printing (ie: OfficeJet K80). In this case HPIJS output is sent
to the "hp" CUPS backend, the backend opens an 1284.4/MLC print
channel, then the data is passed to the actual device. 
--------------------------------------------------------------------
If the LaserJet 2300 is not such a special device like the
OfficeJet K80, then printing should also work with the
generic CUPS "usb" backend - at least for a test.
But for device status and device maintenance via hp-toolbox
you need the hp backend.


Kind Regards
Johannes Meixner
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