CUPS/Troubleshooting
Related articles
This article covers all non-specific (ie, not related to any one printer) troubleshooting of CUPS and printing drivers (but not problems related to printer sharing), including methods of determining the exact nature of the problem, and of solving the identified problem.
Contents
- 1 Introduction
- 2 Problems resulting from upgrades
- 3 Networking issues
- 4 USB printers
-
5 HP issues
- 5.1 CUPS: "/usr/lib/cups/backend/hp failed"
- 5.2 CUPS: Job is shown as complete but the printer does nothing
- 5.3 CUPS: '"foomatic-rip" not available/stopped with status 3'
- 5.4 CUPS: "Filter failed"
- 5.5 CUPS: prints only an empty and an error-message page on HP LaserJet
- 5.6 HPLIP 3.13: Plugin is installed, but HP Device Manager complains it is not
- 5.7 hp-toolbox: "Unable to communicate with device"
- 5.8 hp-setup asks to specify the PPD file for the discovered printer
- 5.9 hp-setup: "Qt/PyQt 4 initialization failed"
- 5.10 hp-setup: finds the printer automatically but reports "Unable to communicate with device" when printing test page immediately afterwards
-
6 Other
- 6.1 Printer "Paused" or "Stopped" with Status "Rendering completed"
- 6.2 Printing fails with unauthorised error
- 6.3 Unknown supported format: application/postscript
- 6.4 Print-Job client-error-document-format-not-supported
- 6.5 Unable to get list of printer drivers
- 6.6 lp: Error - Scheduler Not Responding
- 6.7 "Using invalid Host" error message
- 6.8 Cannot print from LibreOffice
- 6.9 Printer output shifted
- 6.10 Printer becomes stuck after a problem
Introduction
The best way to get printing working is to set 'LogLevel' in /etc/cups/cupsd.conf
to:
LogLevel debug
And then viewing the output from /var/log/cups/error_log
like this:
# tail -n 100 -f /var/log/cups/error_log
The characters at the left of the output stand for:
- D=Debug
- E=Error
- I=Information
- And so on
These files may also prove useful:
-
/var/log/cups/page_log
- Echoes a new entry each time a print is successful -
/var/log/cups/access_log
- Lists all cupsd http1.1 server activity
Of course, it is important to know how CUPS works if wanting to solve related issues:
- An application sends a .ps file (PostScript, a script language that details how the page will look) to CUPS when 'print' has been selected (this is the case with most programs).
- CUPS then looks at the printer's PPD file (printer description file) and figures out what filters it needs to use to convert the .ps file to a language that the printer understands (like PJL, PCL), usually GhostScript.
- GhostScript takes the input and figures out which filters it should use, then applies them and converts the .ps file to a format understood by the printer.
- Then it is sent to the back-end. For example, if the printer is connected to a USB port, it uses the USB back-end.
Print a document and watch error_log
to get a more detailed and correct image of the printing process.
Problems resulting from upgrades
Issues that appeared after CUPS and related program packages underwent a version increment
CUPS stops working
The chances are that a new configuration file is needed for the new version to work properly. Messages such as "404 - page not found" may result from trying to manage CUPS via localhost:631, for example.
To use the new configuration, copy /etc/cups/cupsd.conf.default
to /etc/cups/cupsd.conf
(backup the old configuration if needed) and restart CUPS to employ the new settings.
All jobs are "stopped"
If all jobs sent to the printer become "stopped", delete the printer and add it again. Using the CUPS web interface, go to Printers > Delete Printer.
To check the printer's settings go to Printers, then Modify Printer. Copy down the information displayed, click 'Modify Printer' to proceed to the next page(s), and so on.
All jobs are "The printer is not responding"
On networked printers, you should check that the hostname in the printer's URI resolves to the printer's IP address via DNS, e.g. if your printer's connection looks like this:
lpd://BRN_020554/BINARY_P1
then the hostname 'BRN_020554' needs to resolve to the printer's IP from the server running CUPS. If Avahi is being used, ensure that Avahi's hostname resolution is working.
Alternatively, replace the hostname used in the URI with the printer's IP address.
The PPD version is not compatible with gutenprint
Run:
# /usr/bin/cups-genppdupdate
And restart CUPS (as pointed out in gutenprint's post-install message)
Printers are not present in the print dialog for GTK3 applications
A recent upgrade of GTK3 (3.22) requires the gtk3-print-backends package for printers to be listed in GTK3 print dialogs. This stops printing from applications like gedit and Firefox, but printers still appear in the CUPS web interface and lpstat, and you can print from the command line and GTK2 applications like GIMP.
Networking issues
Unable to locate printer
Even if CUPS can detect networked printers, you may still end up with an "Unable to locate printer" error when trying to print something. The solution to this problem is to enable Avahi's .local hostname resolution. See CUPS#Network for details.
Old CUPS server
As of CUPS version 1.6, the client defaults to IPP 2.0. If the server uses CUPS <= 1.5 / IPP <= 1.1, the client does not downgrade the protocol automatically and thus cannot communicate with the server. A workaround is to append the version=1.1
option documented at [1] to the URI.
CUPS identifies printer but cannot connect to it
Enable debug logging. If you see Executing backend "/usr/lib/cups/backend/dnssd"...
over and over switch from dnssd to socket in the printer configuration.
Example: socket://192.168.11.6:9100
. The port number can be confirmed via nmap or telnet your-printer-ip 9100
.
USB printers
Conflict with SANE
If you are also running SANE, it's possible that it is conflicting with CUPS. To fix this create a Udev rule marking the device as matched by libsane:
/etc/udev/rules.d/99-printer.rules
ATTRS{idVendor}=="vendor id", ATTRS{idProduct}=="product id", MODE="0664", GROUP="lp", ENV{libsane_matched}="yes"
Conflict with usblp
USB printers can be accessed using two methods: The usblp kernel module and libusb. The former is the classic way. It is simple: data is sent to the printer by writing it to a device file as a simple serial data stream. Reading the same device file allows bi-di access, at least for things like reading out ink levels, status, or printer capability information (PJL). It works very well for simple printers, but for multi-function devices (printer/scanner) it is not suitable and manufacturers like HP supply their own backends. Source: here.
If you have problems getting your USB printer to work, you can try blacklisting the usblp
kernel module:
/etc/modprobe.d/blacklistusblp.conf
blacklist usblp
Custom kernel users may need to manually load the usbcore
kernel module before proceeding.
Once the modules are installed, plug in the printer and check if the kernel detected it by running the following:
# journalctl -e
or
# dmesg
If you are using usblp
, the output should indicate that the printer has been detected like so:
Feb 19 20:17:11 kernel: printer.c: usblp0: USB Bidirectional printer dev 2 if 0 alt 0 proto 2 vid 0x04E8 pid 0x300E Feb 19 20:17:11 kernel: usb.c: usblp driver claimed interface cfef3920 Feb 19 20:17:11 kernel: printer.c: v0.13: USB Printer Device Class driver
If you blacklisted usblp
, you will see something like:
usb 3-2: new full speed USB device using uhci_hcd and address 3 usb 3-2: configuration #1 chosen from 1 choice
HP issues
See also CUPS/Printer-specific problems#HP.
CUPS: "/usr/lib/cups/backend/hp failed"
Make sure dbus is installed and running. If the error persists, try starting avahi-daemon.
Try adding the printer as a Network Printer using the http:// protocol.
CUPS: Job is shown as complete but the printer does nothing
This happens on HP printers when you select the (old) hpijs driver (e.g. the Deskjet D1600 series). Use the hpcups driver instead.
Some HP printers require their firmware to be downloaded from the computer every time the printer is switched on. If there is an issue with udev (or equivalent) and the firmware download rule is never fired, you may experience this issue. As a workaround, you can manually download the firmware to the printer. Ensure the printer is plugged in and switched on, then run
hp-firmware -n
CUPS: '"foomatic-rip" not available/stopped with status 3'
If receiving any of the following error messages in /var/log/cups/error_log
while using a HP printer, with jobs appearing to be processed while they all end up not being completed with their status set to 'stopped':
Filter "foomatic-rip" for printer printer_name not available: No such file or director
or:
PID pid (/usr/lib/cups/filter/foomatic-rip) stopped with status 3!
make sure hplip has been installed.
CUPS: "Filter failed"
A "filter failed" error can be caused by any number of issues. The CUPS error log should record which filter failed and why.
Missing foomatic-db
Install foomatic-db and foomatic-db-ppds. This fixes it in some cases.
Bad permissions
Change the permissions of the printer USB port. Get the bus and device number from lsusb
, then set the permission using:
lsusb
Bus <BUSID> Device <DEVID>: ID <PRINTERID>:<VENDOR> Hewlett-Packard DeskJet D1360
Then substitute the provided device information to the
# chmod 0666 /dev/bus/usb/<BUSID>/<DEVID>
To make the persistent permission change that will be triggered automatically each time the computer is rebooted, add the following line.
/etc/udev/rules.d/10-local.rules
SUBSYSTEM=="usb", ATTRS{idVendor}=="<VENDOR>", ATTRS{idProduct}=="<PRINTERID>", GROUP="lp", MODE:="666"
Each system may vary, so consult udev#List attributes of a device wiki page.
Avahi not enabled
Start, and enable the avahi-daemon
service.
Out-of-date plugin
This error can also indicate that the plugin is out of date (version is mismatched). If you have installed hplip-pluginAUR, you will need to update the package.
CUPS: prints only an empty and an error-message page on HP LaserJet
There is a bug that causes CUPS to fail when printing images on HP LaserJet (in my case 3380). The bug has been reported and fixed by Ubuntu. The first page is empty, the second page contains the following error message:
ERROR: invalidaccess OFFENDING COMMAND: filter STACK: /SubFileDecode endstream ...
In order to fix the issue, run the following command as root:
# lpadmin -p printer -o pdftops-renderer-default=pdftops
HPLIP 3.13: Plugin is installed, but HP Device Manager complains it is not
The issue might have to do with the file permission change that had been made to /var/lib/hp/hplip.state
. To correct the issue, a simple chmod 644 /var/lib/hp/hplip.state
and chmod 755 /var/lib/hp
should be sufficient. For further information, please read this link.
hp-toolbox: "Unable to communicate with device"
# hp-toolbox # error: Unable to communicate with device (code=12): hp:/usb/printer id
Permission problem
It may be needed to add the user to the lp
and sys
groups.
Virtual CDROM printers
This can also be caused by printers such as the P1102 that provide a virtual CD-ROM drive for MS Windows drivers. The lp dev appears and then disappears. In that case, try the usb-modeswitch and usb-modeswitch-data packages, that lets one switch off the "Smart Drive" (udev rules included in said packages).
Networked printers
This can also occur with network attached printers using dynamic hostnames if the avahi-daemon is not running. Another possibility is that hp-setup failed to locate the printer because the IP address of the the printer changed due to DHCP. If this is the case, consider adding a DHCP reservation for the printer in the DHCP server's configuration.
hp-setup asks to specify the PPD file for the discovered printer
Install and start CUPS before running hp-setup.
hp-setup: "Qt/PyQt 4 initialization failed"
Install python-pyqt4, which is an optdepend of hplip. Alternatively, to run hp-setup with the command line interface, use the -i
flag.
hp-setup: finds the printer automatically but reports "Unable to communicate with device" when printing test page immediately afterwards
This at least happens to hplip 3.13.5-2 for HP Officejet 6500A through local network connection. To solve the problem, specify the IP address of the HP printer for hp-setup to locate the printer.
Other
Printer "Paused" or "Stopped" with Status "Rendering completed"
Low ink
When low on ink, some printers will get stuck in "Rendering completed" status and, if it is a network printer, the printer may even become unreachable from CUPS' perspective despite being properly connected to the network. Replacing the low/depleted ink cartridge(s) in this setting will return the printer to "Ready" status and, if it is a network printer, will make the printer available to CUPS again.
Permission issue
Prior to cups 2.0.0-2, if the group set in the Group
directive is also listed in the SystemGroup
directive in /etc/cups/cups-files.conf
, cupsd
will instead run any helper programs with a group of nobody
. However, the helpers may need to write to printer devices, which are created with user root
and group lp
, and will be unable to if they are run with a group of nobody
, causing the print queue to become "Paused" or "Stopped".
To fix this, ensure that the the Group
directive is set to lp
, and the SystemGroup
directive does not include lp
.
Fixed in Arch with [2].
Printing fails with unauthorised error
If a remote printer requests authentication CUPS will automatically add an AuthInfoRequired
directive to the printer in /etc/cups/printers.conf
. However, some graphical applications (for instance, some versions of LibreOffice [3]) have no way to prompt for credentials, so printing fails.
To fix this include the required username and password in the URI.
See [4], [5],
Unknown supported format: application/postscript
Comment the lines:
application/octet-stream application/vnd.cups-raw 0 -
from /etc/cups/mime.convs
, and:
application/octet-stream
in /etc/cups/mime.types
.
Print-Job client-error-document-format-not-supported
Try installing the foomatic packages and use a foomatic driver.
Unable to get list of printer drivers
(Also applicable to error "-1 not supported!")
Try to remove Foomatic drivers or refer to CUPS/Printer-specific problems#HPLIP Driver for a workaround.
lp: Error - Scheduler Not Responding
If you get this error, ensure CUPS is running, the environmental variable CUPS_SERVER
is unset, and that /etc/cups/client.conf
is correct.
"Using invalid Host" error message
Try adding ServerAlias *
into /etc/cups/cupsd.conf
.
Cannot print from LibreOffice
If you can print a test page from the CUPS web interface, but not from LibreOffice, try to install the a2ps package.
Printer output shifted
This seems to be caused by the wrong page size being set in CUPS.
Printer becomes stuck after a problem
When an issue arises during printing, the printer in CUPS may become unresponsive. lpq
reports that the printer is not ready
. It can be reactivated using cupsenable
. To automatically have CUPS reactivate the printer, change ErrorPolicy from the default stop-printer
to retry-this-job
.