[cups.bugs] [HIGH] STR #3823: Cups silently pauses, needs to be prodded to continue printing

[kernel.pkts]

DO NOT REPLY TO THIS MESSAGE.  INSTEAD, POST ANY RESPONSES TO THE LINK BELOW.

[STR New]

We have a Zebra label printer, that prints barcodes using the ZPL (Zebra
printing language).  It's accessible via tcp/ip, by connecting to port
9100 (the normal jetdirect socket).  We have cups running on an XServe
running SnowLeopard.  Jobs are submitted through a web page which calls
'lpr -PZebra_Technologies_ZTC_GX430t -o raw' with the data.

The printer operates normally 99% of the time, but occasionally print jobs
stop being printed and build up in the queue.  We've tried:

1. Telnetting to the printer (port 23 has a basic control panel) and
resetting the printer from the menu.
2. Power cycling the printer.
3. Checking cups.

According to Cups, the printer is fine, and jobs are queued, ready to
print.  At this point, I paused the queue, and then resumed the queue, and
suddenly the printer started printing again, emptying the queue.  No errors
or warnings appeared in the logs.  The printer printed a job earlier in the
day.

The next time this happens, I'll try to do some tcpdump packet capturing,
dtruss, etc, etc, but this bug report may time out before that happens, as
we print infrequently.

Link: http://www.cups.org/str.php?L3823
Version: 1.4.5