Unable to print to parallel port

Bug #235670 reported by Jason Schindler on 2008-05-29
Affects Status Importance Assigned to Milestone
cupsys (Ubuntu)
Nominated for Intrepid by Johne
udev (Ubuntu)
Nominated for Intrepid by Johne

Bug Description

Binary package hint: udev

It appears that the solution to this problem has been known for sometime, but I just experienced it with a fresh install (and update) of Kubuntu 8.04. I was unable to find the bug on launchpad... hopefully this one isn't a duplicate.

I'm running Kubuntu 8.04

After installing my Brother HL-2070N using the deb packages provided by Brother, the printer was visible in CUPS and I was able to complete the configuration of it (change the uri from the default 'usb' to 'parallel:/dev/lp0'). When I attempted to print a test page, the job was immediately placed on 'Hold' and would never print. Using the CUPS web configuration tool, I saw the following message next to the printer name:

""/dev/lp0": Permission denied"

I found the solution in the following forum posts:


After updating the "/etc/udev/rules.d/40-permissions.rules" file from:

# Printers and Parallel devices
SUBSYSTEM=="printer", GROUP="lp"
SUBSYSTEM=="ppdev", GROUP="lp"
SUBSYSTEM=="usb", KERNEL=="lp[0-9]*", GROUP="lp"


# Printers and Parallel devices
SUBSYSTEM=="printer", OWNER="lp", GROUP="lp"
SUBSYSTEM=="ppdev", GROUP="lp"
SUBSYSTEM=="usb", KERNEL=="lp[0-9]*", OWNER="lp", GROUP="lp"

I was able to print without issue.

Till Kamppeter (till-kamppeter) wrote :

Moving to udev, due to

till@till-laptop:~$ dpkg -S /etc/udev/rules.d/40-permissions.rules
udev: /etc/udev/rules.d/40-permissions.rules

Please fix this ASAP in the udev package, currently printing via the parallel port is impossible under Ubuntu.

Changed in cupsys:
importance: Undecided → Critical
milestone: none → intrepid-alpha-1
status: New → Triaged

Why do the devices need to be owned by "lp" ? Permission for the "lp" group is sufficient, whatever daemon or tools are accessing these devices should be in group "lp"

Changed in udev:
status: Triaged → Won't Fix
Till Kamppeter (till-kamppeter) wrote :

Can you try the following:

Modify /etc/udev/rules.d/40-permissions.rules back to its old state, without your workaround (/dev/lp0 should have owner root, group lp, and 660 permissions).

Now do

sudo aa-complain cupsd

Can you print now?

Can you post the messages containing "audit" in your /var/log/syslog?

You get back to the standard AppArmor configuration with

sudo aa-enforce cupsd

Changed in cupsys:
status: New → Incomplete
Jason Schindler (jschindler) wrote :

I reverted the "/etc/udev/rules.d/40-permissions.rules" file back to:

# Printers and Parallel devices
SUBSYSTEM=="printer", GROUP="lp"
SUBSYSTEM=="ppdev", GROUP="lp"
SUBSYSTEM=="usb", KERNEL=="lp[0-9]*", GROUP="lp"

Afterwards, I was not able to print a test page and received the same error as before in the CUPS web configuration tool:

"Unable to open device file "/dev/lp0": Permission denied"

I then ran the command above:

jschindler@centime:~$ sudo aa-complain cupsd
[sudo] password for jschindler:
Setting /etc/apparmor.d/usr.sbin.cupsd to complain mode.

In complain mode, I'm still unable to print a test page.

jschindler@centime:~$ cat /var/log/syslog | grep "audit"
Jun 3 08:10:49 centime kernel: [ 29.995251] audit: initializing netlink socket (disabled)
Jun 3 08:10:49 centime kernel: [ 29.995267] audit(1212498624.236:1): initialized
Jun 3 08:10:52 centime kernel: [ 57.754790] audit(1212498652.982:2): type=1502 operation="inode_permission" requested_mask="a::" denied_mask="a::" name="/dev/tty" pid=5127 profile="/usr/sbin/cupsd" namespace="default"

If you need additional information from me, please let me know.

Jayson Rowe (jayson.rowe) wrote :

Since it's been a very long time since any additional info was added to this bug, I'm just checking to see if this is still an issue, and find out what additional work should be done on this bug.

Victor Vargas (kamus) wrote :

We are closing this bug report because it lacks the information we need to investigate the problem, as described in the previous comments. Please reopen it if you can give us the missing information, and don't hesitate to submit bug reports in the future. To reopen the bug report you can click on the current status, under the Status column, and change the Status back to "New". Thanks again!

Changed in cupsys (Ubuntu):
status: Incomplete → Invalid
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