cups 1.2 - no output

Jan-Espen Pettersen sigsegv at radiotube.org
Tue Jul 4 20:39:07 UTC 2006


Rainer Heesen wrote:
> root at desktop ~# echo test > /dev/ulpt0
> bash: /dev/ulpt0: Device busy
>
> so I think it is not a cups problem, but what kind of program make the usb 
> device busy?
>   
It can't be any other program if fstat is not reporting anything. I've
been reading on the usb printer standard, and the ulpt code. I found
that it will return 'device busy' (EBUSY) in one more condition other
than that it is in use by another program. It will first do a soft reset
on the printer, telling it to forget everything about previous request
and/or errors. Then it'll wait for the printer to set it's state to
Selected (ie. online). If the printer doesn't set its state to online
FreeBSD will return EBUSY (device busy).

You can try running your kernel in verbose mode ('boot -v' from the
loader), and if this is the case you'll see series of messages on the
console like:
ulpt_open: waiting a while
...

To get your printer working again, maybe you can unplug, powercycle (ie.
hard reset) your printer. And then try /dev/unlpt0. (No reset) 'echo
test > /dev/unlpt0' is an effective test.

Maybe your printer sets the online bit correctly if it doesn't receive
the reset.
And otherwise if you can confirm that the printer is not online, then
maybe you can manually tell it to get online or power up. (By pushing an
eventual 'power up'/'online' button on the printer itself)


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