[SOLVED] - CUPS mess. No printer - no connection to printing service

[harisano]

Hi,

I am very new to Linux so please forgive me if I ask very stupid questions.
Also, I would like to say that I did search for possible answers online, and I still can't get the damn thing to work. Therefore this post.

OK, so this is the config:

Linux: Linux Mint 19.3 Tricia
Printer: Brother DCP-L3550CDW
Connection: WLAN

Let me start off by saying that everything did work when I first installed it. And then *something* happened (I am definitely not ruling out human error), and now it doesn't.

So, in the beginning; I got this printer --> went online (here: https://support.brother.com/g/b/downloa ... _eu&os=128) --> got the driver package --> did the whole unpack and install thing --> specified printer's IP during the install --> everything installed beautifully!

Then I was doing something a couple of days later, and now when I open the "Printers" config, my printer is gone. Instead there is "Printing service not available. Start the service on this computer or connect to other server."

If I try and click "server" --> "connect" --> "Connect to CUPS server: /run/cups/cups.sock", I get a CUPS server error: There was an error during the CUPS operation: 'failed to connect to server'.

First thing I did was try and do a reinstall. I uninstalled the existing printing and scanning drivers, then tried to re-install. That didn't go well. The installation did finish, but with - what I believe to be - error messages during the install.
For example, there are these lines that don't sound too good:

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dpkg -i --force-all dcpl3550cdwpdrv-1.0.2-0a.i386.deb
Selecting previously unselected package dcpl3550cdwpdrv:i386.
(Reading database ... 319369 files and directories currently installed.)
Preparing to unpack dcpl3550cdwpdrv-1.0.2-0a.i386.deb ...
Unpacking dcpl3550cdwpdrv:i386 (1.0.2-0) ...
Setting up dcpl3550cdwpdrv:i386 (1.0.2-0) ...
Restarting cups (via systemctl): cups.service.
lpinfo: Bad file descriptor
lpadmin -p DCPL3550CDW -E -v usb://dev/usb/lp0 -P /usr/share/cups/model/Brother/brother_dcpl3550cdw_printer_en.ppd
lpadmin: Unable to connect to server: Bad file descriptor
Restarting cups (via systemctl): cups.serviceJob for cups.service failed.
See "systemctl status cups.service" and "journalctl -xe" for details.
 failed!

Also, when it comes to the step where I am to specify the printer's IP address, it shows this:

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lpadmin -p DCPL3550CDW -v socket://192.168.0.105 -E
lpadmin: Unable to connect to server: Bad file descriptor

OK. So that didn't work.
Next idea I had was to remove and purge cups, re-install, the re-install the printer driver, and then everything would be great.
So that's what I did. I did both a

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sudo apt-get remove cups

and a

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sudo apt-get purge cups

on the cups package, re-installed it, re-installed the printer drivers - still nothing.

And I kinda had an idea that it wouldn't work, bc right after I ran the remove and purge commands on cups, I checked the /etc/cups folder - the printers.config file looked the same as before, which is kinda funny, coz I thought that purge was supposed to - well, purge - the config files as well?

Anyways, now I'm kinda stuck.
I guess it's because I don't really understand the cups service and what it does? I have a strange feeling that all the pieces are there, I just can't put them together.
So yeah, would really appreciate some help.

Cheers,
- h

[LanceM]

Did you use the terminal to uninstall? viewtopic.php?p=1752268#p1752268
Once uninstalled, you can try installing again. Before you were asked about URI, did you select the number for Auto? Did you get the ip address from making the printer print the network sheet?

[harisano]

Hi LanceM,

Thanks for your reply.

Did you use the terminal to uninstall? viewtopic.php?p=1752268#p1752268

Well, yes, but not quite like that. I just ran the brother uninstall files.
But after seeing your post, I did as described there too.

Once uninstalled, you can try installing again.

And so I did. Again; the same errors:

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The following packages have unmet dependencies:
 ia32-libs : Depends: libasound2-plugins:i386
             Depends: libpulse-mainloop-glib0:i386
             Depends: libpulsedsp:i386
             Depends: libsdl-image1.2:i386
             Depends: libsdl-mixer1.2:i386
             Depends: libsdl-net1.2:i386
             Depends: libsdl-ttf2.0-0:i386
             Depends: libsdl1.2debian:i386
E: Unable to correct problems, you have held broken packages.
dpkg -x dcpl3550cdwpdrv-1.0.2-0.i386.deb /
dpkg-deb: building package 'dcpl3550cdwpdrv' in 'dcpl3550cdwpdrv-1.0.2-0a.i386.deb'.
dpkg -b ./brother_driver_packdir dcpl3550cdwpdrv-1.0.2-0a.i386.deb
dpkg -i --force-all dcpl3550cdwpdrv-1.0.2-0a.i386.deb
Selecting previously unselected package dcpl3550cdwpdrv:i386.
(Reading database ... 319356 files and directories currently installed.)
Preparing to unpack dcpl3550cdwpdrv-1.0.2-0a.i386.deb ...
Unpacking dcpl3550cdwpdrv:i386 (1.0.2-0) ...
Setting up dcpl3550cdwpdrv:i386 (1.0.2-0) ...
Restarting cups (via systemctl): cups.service.
lpinfo: Bad file descriptor
lpadmin -p DCPL3550CDW -E -v usb://dev/usb/lp0 -P /usr/share/cups/model/Brother/brother_dcpl3550cdw_printer_en.ppd
lpadmin: Unable to connect to server: Bad file descriptor
Restarting cups (via systemctl): cups.serviceJob for cups.service failed.
See "systemctl status cups.service" and "journalctl -xe" for details.
 failed!
#

Before you were asked about URI, did you select the number for Auto?

No, I did not. I chose 0 for "Specify IP address". That's what Brother says on their website!

Did you get the ip address from making the printer print the network sheet?

Exactly! And the address is 100% correct, since I used the same IP address before when it worked. Also, my phone finds the printer at that very address.

Cheers,
- h

[LanceM]

Try Auto, but you have to uninstall again first. My Brother requires Auto, as did the several others I've installed for friends. Yours may be different, but it's worth a try. Do you have a Timeshift snapshot from before this all started?

[harisano]

Try Auto, but you have to uninstall again first. My Brother requires Auto. Yours may be different, but it's worth a try. Do you have a Timeshift snapshot from before this all started?

I also did auto - no joy.
Yeah I've got a timeshift snapshot form a while back. I'm just like, really, stubborn. Like, there is something fixable here, and I really wanna fix it.

- h

[LanceM]

I have had to go to the printer menu and have it search for networks, then press the WPS button on the router while it's searching, so it can connect.

[brian_p]

Please let us have what is given by

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avahi-browse -rt _ipp._tcp

and

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avahi-browse -rt _uscan._tcp

[harisano]

Please let us have what is given by

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avahi-browse -rt _ipp._tcp

and

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avahi-browse -rt _uscan._tcp

By avahi-browse -rt _ipp._tcp (some stuff redacted [XXX] as it seemed like private information):

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+ wlp4s0 IPv6 Brother DCP-L3550CDW series                   Internet Printer     local
+ wlp4s0 IPv4 Brother DCP-L3550CDW series                   Internet Printer     local
= wlp4s0 IPv6 Brother DCP-L3550CDW series                   Internet Printer     local
   hostname = [XXXXXXXXXX.local]
   address = [192.168.0.105]
   port = [XXX]
   txt = ["mopria-certified=1.3" "print_wfds=T" "UUID=e3248000-80ce-11db-8000-3c2af4ab8641" "PaperMax=legal-A4" "kind=document,envelope,label,postcard" "URF=SRGB24,W8,CP1,IS4-1,MT1-3-4-5-8-11,OB10,PQ4,RS600,V1.4,DM1" "TBCP=F" "Transparent=T" "Binary=T" "PaperCustom=T" "Scan=T" "Fax=F" "Duplex=T" "Copies=T" "Color=T" "usb_CMD=PJL,PCL,PCLXL,URF" "usb_MDL=DCP-L3550CDW series" "usb_MFG=Brother" "priority=25" "adminurl=XXXXXXXXXXXXXXXXXXX.html" "product=(Brother DCP-L3550CDW series)" "ty=Brother DCP-L3550CDW series" "note=" "rp=ipp/print" "pdl=application/octet-stream,image/urf,image/jpeg,image/pwg-raster" "qtotal=1" "txtvers=1"]
= wlp4s0 IPv4 Brother DCP-L3550CDW series                   Internet Printer     local
   hostname = [XXXXXXXXXX.local]
   address = [192.168.0.105]
   port = [XXX]
   txt = ["mopria-certified=1.3" "print_wfds=T" "UUID=e3248000-80ce-11db-8000-3c2af4ab8641" "PaperMax=legal-A4" "kind=document,envelope,label,postcard" "URF=SRGB24,W8,CP1,IS4-1,MT1-3-4-5-8-11,OB10,PQ4,RS600,V1.4,DM1" "TBCP=F" "Transparent=T" "Binary=T" "PaperCustom=T" "Scan=T" "Fax=F" "Duplex=T" "Copies=T" "Color=T" "usb_CMD=PJL,PCL,PCLXL,URF" "usb_MDL=DCP-L3550CDW series" "usb_MFG=Brother" "priority=25" "adminurl=XXXXXXXXXXXXXXXXXXX.html" "product=(Brother DCP-L3550CDW series)" "ty=Brother DCP-L3550CDW series" "note=" "rp=ipp/print" "pdl=application/octet-stream,image/urf,image/jpeg,image/pwg-raster" "qtotal=1" "txtvers=1"]

and avahi-browse -rt _uscan._tcp :

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+ wlp4s0 IPv4 Brother DCP-L3550CDW series                   _uscan._tcp          local
= wlp4s0 IPv4 Brother DCP-L3550CDW series                   _uscan._tcp          local
   hostname = [XXXXXXXXXX.local]
   address = [192.168.0.105]
   port = [XXX]
   txt = ["duplex=F" "is=adf,platen" "cs=binary,grayscale,color" "UUID=e3248000-80ce-11db-8000-3c2af4ab8641" "pdl=application/pdf,image/jpeg" "note=" "ty=Brother DCP-L3550CDW series" "rs=eSCL" "representation=[XXXXXXXXXX.local]./icons/device-icons-128.png" "adminurl=[XXXXXXXXXX.local]./net/net/airprint.html" "vers=2.63" "txtvers=1"]

[harisano]

Also I get this when I run systemctl --failed

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systemctl --failed
  UNIT         LOAD   ACTIVE SUB    DESCRIPTION                                                                                                                                 
● cups.path    loaded failed failed CUPS Scheduler                                                                                                                              
● cups.service loaded failed failed CUPS Scheduler                                                                                                                              
● cups.socket  loaded failed failed CUPS Scheduler                                                                                                                              

LOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB    = The low-level unit activation state, values depend on unit type.

3 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.

cheers,
- h

[brian_p]

Thank you for the two outputs. We will put them on one side for the time being because it is now clear that your cups service is not starting. This was also (as we now see) indictated in a previous post of yours. It is obvious that this needs to be fixed for you to print.

lpinfo: Bad file descriptor
lpadmin -p DCPL3550CDW -E -v usb://dev/usb/lp0 -P /usr/share/cups/model/Brother/brother_dcpl3550cdw_printer_en.ppd
lpadmin: Unable to connect to server: Bad file descriptor
Restarting cups (via systemctl): cups.serviceJob for cups.service failed.
See "systemctl status cups.service" and "journalctl -xe" for details.
failed!

See if the journal provides any more useful detail. My experience is that it often doesn't.

Also try backing up /etc/cups/cupsd.conf and replacing it:

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cp /usr/share/cups/cupsd.conf.default /etc/cups/cupsd.conf

Restart the service:

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systemctl start cups

[harisano]

Brian, this is amazing! In the sense that it worked! Thank you so much!

Thank you for the two outputs. We will put them on one side for the time being because it is now clear that your cups service is not starting. This was also (as we now see) indictated in a previous post of yours. It is obvious that this needs to be fixed for you to print.

lpinfo: Bad file descriptor
lpadmin -p DCPL3550CDW -E -v usb://dev/usb/lp0 -P /usr/share/cups/model/Brother/brother_dcpl3550cdw_printer_en.ppd
lpadmin: Unable to connect to server: Bad file descriptor
Restarting cups (via systemctl): cups.serviceJob for cups.service failed.
See "systemctl status cups.service" and "journalctl -xe" for details.
failed!

See if the journal provides any more useful detail. My experience is that it often doesn't.

Also try backing up /etc/cups/cupsd.conf and replacing it:

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cp /usr/share/cups/cupsd.conf.default /etc/cups/cupsd.conf

Restart the service:

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systemctl start cups

However, if you don't mind, explaining why exactly this worked?

I did exactly like you wrote:

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root@tabby:/# cp /usr/share/cups/cupsd.conf.default /etc/cups/cupsd.conf
root@tabby:/# systemctl start cups

I can now see that the CUPS service started, partly for two reasons:

• 1. When I open up "Printers", I can see my printer there.

• 2. When I run systemctl --failed

, there are only 2 failed units, instead of the 3 before:

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systemctl --failed
  UNIT        LOAD   ACTIVE SUB    DESCRIPTION                                                                                                                                  
● cups.path   loaded failed failed CUPS Scheduler                                                                                                                               
● cups.socket loaded failed failed CUPS Scheduler                                                                                                                               

LOAD   = Reflects whether the unit definition was properly loaded.
ACTIVE = The high-level unit activation state, i.e. generalization of SUB.
SUB    = The low-level unit activation state, values depend on unit type.

2 loaded units listed. Pass --all to see loaded but inactive units, too.
To show all installed unit files use 'systemctl list-unit-files'.

Can you explain what just happened with those 2 lines of code you helped me with. And why are there still 2 failed units?
Or point me to some literature that I could read myself, to understand this?

All in all; thanks a lot! I can print again!

cheers,
- h

[brian_p]

All in all; thanks a lot! I can print again!

Splendid.

Can you explain what just happened with those 2 lines of code you helped me with.

Do you mean the two avahi-browse commands?

And why are there still 2 failed units?

Pass. I think they should be started when the cups service starts. Try

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systemctl start cups.socket

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systemctl start cups.path

Or do stop followed by start.

Or point me to some literature that I could read myself, to understand this?

Perhaps

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man systemctl

[harisano]

Thanks a lot - I'm gonna educate myself some more on this as soon as I can get around to it. The important thing is that printing works now.

Marking issue as solved now.

cheers,
- h

All in all; thanks a lot! I can print again!

Splendid.

Can you explain what just happened with those 2 lines of code you helped me with.

Do you mean the two avahi-browse commands?

And why are there still 2 failed units?

Pass. I think they should be started when the cups service starts. Try

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systemctl start cups.socket

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systemctl start cups.path

Or do stop followed by start.

Or point me to some literature that I could read myself, to understand this?

Perhaps

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man systemctl

[brian_p]

Thanks a lot - I'm gonna educate myself some more on this as soon as I can get around to it. The important thing is that printing works now.

I am pleased things worked out for you.

As part of your education, you may be interested to know that you can do driverless printing with your DCP-L3550CDW: https://wiki.debian.org/CUPSDriverlessPrinting.

You can also do driverless scanning: https://github.com/alexpevzner/sane-airscan.

Both can be done without interfering with or removing your present software setup. If you ever decided to test sane-airscan (a 30 minute job), I would be very interested in the outcome.