Strange USB printer dissapearance - Stranger workaround

Steven P. Ulrick ulrick2 at faith4miracle.org
Tue Jul 13 17:46:32 UTC 2004


Hello, Everyone :)
If any of you are on the CUPS list, I do apologize, but I have my
suspicions that this MIGHT be Fedora related, so here goes.
Before I launch into my detailed diagnosis, and temporary treatment, of
this issue, I will give a synopsis of my USB printer woe's.

Sometime after a recent fresh install of Fedora Core 2 (This was an
"Everything" install.  Also, it was not an upgrade) our Samsung ML1250
Laser Printer dissapeared.  Well, of course I mean that it's
configuration settings dissapeared.  After some dinking around, I got it
to work again, but at first I just didn't know exactly what I had done
to fix it.  I've had this printer dissapear since the original time that
it dissappeared, and the only thing that I could remember was that I
restarted CUPS (NOT "started" it, as it was already running, but
"restarted" it) and, voila, I had our printer back.  I began to have
some supspicions, hence the experiment that I refer to below.  I will
just quote in it's entirety my posting to the CUPS list:

-----------------------------------------------------------------------

Hello, Everyone :)
I just ran an experiment, and the results were very interesting.  For
the sake of (hopefully) clarity, I will describe what I found in a
numbered list.

1. Checked to see that our printer hadn't dissappeared.
2. It hadn't dissappeared, so as root, I ran "/sbin/telinit 1"  While
the appropriate services were shutting down, I saw CUPS shut down
successfully.  I then checked to make sure that CUPS was actually in the
startup sequence for runlevel 5.  It definitely was (and still is)
3. I then ran "/sbin/telinit 5"  I watched the messages roll by, and I
was told that CUPS had started up successfully. To quote the exact words
of the startup sequence message, it started "OK"
4. I logged into my user account (non-root) and checked to see if our
printer was there (using "kcontrol | peripherals | printers").  It was
not!
5. Before I proceeded any further, I checked to see if CUPS was running.
 It was.
6. With "kcontrol | peripherals | printers" open on our monitor, I, as
root, ran "/etc/init.d/cups restart"  Please remember, before I did
this, "system-config-services" claimed that CUPS was running, and the
runlevel 5 startup sequence confirms that.
7. After entering the command "/etc/init.d/cups restart", I watched
kcontrol on our monitor, hit the enter button on our keyboard, and guess
what?  Our printer reappeared!

In summary, CUPS appears to start/shutdown correctly when
rebooting/switching runlevels.  After rebooting/switching runlevels, our
printer is "gone"  Checking to see whether CUPS is running reveals that
apparently it is.  But still, no printer.  I then "restart" a service
(CUPS) that all signs lead me to believe is actually running, and our
printer "reappears"  Do I have any idea what this all means?  No Way! :)
If you have any further questions for me, please feel free to let me
know.
As I mentioned before, our system information is contained in the
original message on this thread.  But, to clarify, the version of CUPS
that I am using is the official Fedora Core 2 released update
(cups-1.1.20-11.1)

Have a Great Day :)
Steven P. Ulrick

P.S.: I need to go to bed before I go to work later, but I will check
the above information for reproducibility.  My strong suspicion is that
it will be 100% reproducible, since everytime I've got our printer back
before, I had restarted CUPS (with no reason to suspect that it wasn't
running to begin with)

-----------------------------------------------------------------------

I've tried the above test at least one more time, with the exact same
results.  CUPS appears to start successfuly, it appears to be running
normally, and the printer is completely functional.  Switch runlevels,
(I believe rebooting would cause the problem also), go back to runlevel
5, CUPS appears to be running, but no printer.  Restart CUPS, printer
reappears.  My honest opinion?  I don't have a clue about what's going
on, only that my temporary workaround works every time, and it works
perfectly.
I tried the same experiment in GNOME.  After /sbin/telinit 1 and then
/sbin/telinit 5, I went to http://localhost:631 and clicked on "Manage
Printers"  It said that I had no printers.  (I also have discovered that
/etc/cups/cupsd.conf says that I do have a printer configured)  I
proceeded to run "/etc/init.d/cups restart"  I then merely refreshed the
browser, and guess what?  All of a sudden, I had our printer back :)

Anyway, that's all I have for now.  If you need any further information,
please feel free to let me know, and I'll be glad to oblige :)

Steven P. Ulrick





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