Duplicate printer showing in apps but not in CUPS, how to remove??

[brian_p]

There are three bugs here IMO.

1. Non-operative printer, as discussed.

Ok.

2. Non-operative printer not appearing in the Printers control panel therefore unable to be disabled or inspected by a regular computer user who is unfamiliar with the command line.

Not a bug. The Printers control panel shows only locally installed print queues. There will be a PPD in /etc/cups/ppd for them and Firefox will display the local queues. Discovery of IPP printers on the network by Firefox does not use CUPS, so there is no PPD and hence no local queue.

3. The same printer appearing twice in the first place. The system should recognise that this is the same printer and show only the best method of connecting to it.

There is actually only one entry for the printer; the other entry is a queue. As many different queue destinations (entries in a dialog) as needed can be set up. One for duplex printing, one for single-sided printing etc. If you do not want to see a destination, remove it (lpadmin -x destination) and/or purge cups-browsed from the system

[ajm83]

Ok.


Not a bug. The Printers control panel shows only locally installed print queues. There will be a PPD in /etc/cups/ppd for them and Firefox will display the local queues. Discovery of IPP printers on the network by Firefox does not use CUPS, so there is no PPD and hence no local queue.

Hmmm. Not sure I agree with that. It may be 'not a bug' as in 'it works as designed' but then IMO the design ought to tie all this in together.

Let me put it this way - if a printer is appearing in the print window of a GUI application, it should be manageable in the GUI control panel. As a user I don't really care how it works behind the scenes or how it was auto-discovered. I shouldn't even need to know the terms CUPS, Avahi, and so on to be able to achieve what I would consider to be very basic administration of the computer.

The control panel itself even has a tick-box to hide and show 'Discovered Printers' ... ticking/unticking it makes no difference though. So presumably that is only for printers discovered in The Right Way.

There is actually only one entry for the printer; the other entry is a queue. As many different queue destinations (entries in a dialog) as needed can be set up. One for duplex printing, one for single-sided printing etc. If you do not want to see a destination, remove it (lpadmin -x destination) and/or purge cups-browsed from the system

Okay, that makes sense, thanks for the tip.

[brian_p]

Hmmm. Not sure I agree with that. It may be 'not a bug' as in 'it works as designed' but then IMO the design ought to tie all this in together.

You can only manage a printer or a print server if you have local control of it; that is, you need a local queue to be set up. system-config-printer is one utility to do this; cups-browsed is another which does it automatically for you. The design enables you to get what *you* want and has been central to CUPS since its inception. s-c-p shows only local queues, as does the CUPS web interface. If you see a remote CUPS server or printer as having a printer service which could be useful to you, you add it as a local queue.

Let me put it this way - if a printer is appearing in the print window of a GUI application, it should be manageable in the GUI control panel. As a user I don't really care how it works behind the scenes or how it was auto-discovered. I shouldn't even need to know the terms CUPS, Avahi, and so on to be able to achieve what I would consider to be very basic administration of the computer.

Print dialogs get their entries for remote printers in different ways. LibreOffice uses CUPS, Firefox doesn't. IMO, it would be better and less confusing for users it the two were aligned. Don't forget that print dialogs construct their entries independently of a user. If he wants to manage what is shown, he needs to control it via a local queue. I gave you an example of that a couple of posts back. In the interests of user friendliness, it shouldn't need to be done.

I can see where you are coming from, but think on. Dispay of destinations and management of them are not the same. (However, the non-working entry in Firefox, which has been about for years, is a pain).

Now look have a read of

https://wiki.debian.org/DriverlessPr...rless_Printing

and explore how this is used by LibreOffice.

The control panel itself even has a tick-box to hide and show 'Discovered Printers' ... ticking/unticking it makes no difference though. So presumably that is only for printers discovered in The Right Way.

I've no idea. The option doesn't do anything for me.