Unable to open device file "/dev/lpt0": Permission denied

Wed Apr 23 13:35:12 UTC 2008

Christian Zachariasen wrote:
> On Wed, Apr 23, 2008 at 4:53 AM, David Reedy Jr <davidrjr at comcast.net 
> <mailto:davidrjr at comcast.net>> wrote:
>
>     On Tuesday 22 April 2008 10:40:25 am Roland Smith wrote:
>     > On Tue, Apr 22, 2008 at 10:08:37AM -0500, David Reedy Jr wrote:
>     > > > IICR, the print device should belong to the cups group. At
>     least,
>     > > > that's my working setup.
>     > > >
>     > > > I have the following in /etc/devfs.conf:
>     > > >
>     > > > # Give cups printer access
>     > > > own     lpt0    root:cups
>     > > > perm    lpt0    0660
>     > >
>     > > Thanks for the info. This didn't actually fix the problem, but I
>     > > know it was needed since I read somewhere that everything that
>     > > cupsd spawns runs as cups.
>     > >
>     > > What I ended up doing was resetting my cupsd.conf to default and
>     > > redid my settings. I must have had a typo in there somewhere
>     before
>     > > because as soon as I restarted cupsd after making the changes, the
>     > > parallel and usb ports suddenly became available as devices
>     for the
>     > > printer.
>     >
>     > It happens. :-)
>     >
>     > > I had previously selected lpd and then manually specified the uri
>     > > as parallel:/dev/lpt0.
>     > >
>     > > The laser on the parallel port is now working fine.
>     >
>     > Good.
>     >
>     > > I also went ahead
>     > > and setup my deskjet on usb:/dev/ulpt0. Print test pages get
>     marked
>     > > as completed but nothing actually comes out of the printer. Still
>     > > trying to figure that one out.
>     >
>     > Have a look at the cups logfiles in /var/log/cups. They should give
>     > you some pointers. You'll probably need to set the device
>     permissions
>     > for ulpt in devfs.rules, not devfs.conf!
>     >
>     I got the rules setup in devfs.rules, no problem. When I turn on the
>     printer it's detected...
>
>     ulpt0: <HP Deskjet 3840, class 0/0, rev 2.00/1.00, addr 2> on uhub0
>     ulpt0: using bi-directional mode
>
>     and things get set right permission-wise...
>
>     crw-rw----  1 root  cups        0,  88 Apr 22 21:20 /dev/ulpt0
>
>     according to /var/log/cups/error_log it prints...
>
>     I [22/Apr/2008:21:20:03 -0500]
>     Started "/usr/local/libexec/cups/cgi-bin/printers.cgi" (pid=756)
>     I [22/Apr/2008:21:20:03 -0500] [Job 47] Adding start banner page
>     "none".
>     I [22/Apr/2008:21:20:03 -0500] [Job 47] Adding job file of type
>     application/postscript.
>     I [22/Apr/2008:21:20:03 -0500] [Job 47] Adding end banner page "none".
>     I [22/Apr/2008:21:20:03 -0500] [Job 47] Queued on "inkjet" by "root".
>     I [22/Apr/2008:21:20:03 -0500] [Job 47] Started
>     filter /usr/local/libexec/cups/filter/pstops (PID 757)
>     I [22/Apr/2008:21:20:03 -0500] [Job 47] Started
>     filter /usr/local/libexec/cups/filter/pstoraster (PID 758)
>     I [22/Apr/2008:21:20:03 -0500] [Job 47] Started
>     filter /usr/local/libexec/cups/filter/rastertohp (PID 759)
>     I [22/Apr/2008:21:20:03 -0500] [Job 47] Started
>     backend /usr/local/libexec/cups/backend/usb (PID 760)
>     I [22/Apr/2008:21:20:06 -0500]
>     Started "/usr/local/libexec/cups/cgi-bin/printers.cgi" (pid=761)
>     I [22/Apr/2008:21:20:06 -0500] [Job 47] Completed successfully.
>     I [22/Apr/2008:21:20:17 -0500]
>     Started "/usr/local/libexec/cups/cgi-bin/printers.cgi" (pid=762)
>
>     but the job disappears into some sort of black hole. Nothing prints.
>     Printer just sits there peacefully doing nothing.
>
>     >From printers.conf for this printer...
>
>     <Printer inkjet>
>     Info HP DeskJet 3845
>     Location Bottom
>     DeviceURI usb:/dev/ulpt0
>     State Idle
>     StateTime 1208917161
>     Accepting Yes
>     Shared Yes
>     JobSheets none none
>     QuotaPeriod 0
>     PageLimit 0
>     KLimit 0
>     AllowUser root
>     AllowUser davidrjr
>     OpPolicy default
>     ErrorPolicy stop-printer
>     </Printer>
>
>     If anybody has additional insight, I'd sure appreciate it.
>
>     Dave
>
>     > Roland
>
>
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>
> IIRC, you should be able to actually write
>
> echo "something" >> /dev/ulpt0
>
> and it should print? Might be useful for testing and stuff.
Test goes to the same black hole. I think I've found the problem...

uhci0: <Intel 82801BA/BAM (ICH2) USB controller USB-A> port 
0xb400-0xb41f irq 3 at device 31.2 on pci0

Perhaps putting a USB 2.0 controller in this old machine might make a 
difference. :)
>
> Anyway, after a quick bit of googling around for your problem (I've 
> had CUPS problems many times in the past myself and I know how hard it 
> can be) I found this:
>
> Here is a workaround:
>
> In printers.conf () you will probably find a line like this:
>
> DeviceURI usb:/dev/ulpt0
>
> change usb: to file:, so that it looks something like this:
>
>
> DeviceURI file:/dev/ulpt0
>
> Then restart cups. Cups will not read any status information from the
> printer, but at least it can print. Be warned about unknown side effects. :)
>
> Jan-Espen Pettersen
>   
>
> ( 
> http://lists.freebsd.org/pipermail/freebsd-questions/2006-June/125703.html 
> )
>
> Christian Zachariasen
>  
>