[Pkg-utopia-maintainers] Bug#969531: avahi-daemon: retrieving printer info blocks printing until shutdown

[Brian Potkin]

On Fri 04 Sep 2020 at 15:23:32 +0200, Michael Hatzold wrote:

> OKI printer B432, conected via USB, no network cable attached.

The B432 is an IPP device; it very likely understands the IPP-over-USB
protocol.

When connected to USB the ipp-usb service is started and ipp-usb takes
control of the only available USB interface.
> 
>    * What led up to the situation?
> Want to print
> 
>    * What exactly did you do (or not do) that was effective (or
>      ineffective)?
> select document, start print dialog, select my printer (config was done via
> CUPS);

Your manually configured iprinter is not being allowed to access the
USB interface. This is not a bug. Please see sections 14, 15 and 16 at

  https://wiki.debian.org/CUPSDriverlessPrinting
  
> Now the printer appears a second time in the list with a different entry. If I
> select this new entry, I am asked for CUPS PW twice, then it (a deamon,
> whatever) starts retriving printer info which *never* completes.

That was a GTK bug at the time. 

>    * What was the outcome of this action?
> Either way, selecting my own entry or the new one made by the daemon, the
> printer does nothing (I waited up to 45 minutes... until I shutdown my system.
> Them during shutdown, there is a pause during which the document gets printed.

Pass.
 
>    * What outcome did you expect instead?
> I want the printer to print after I sent the job.
> 
> 
> *** End of the template - remove these template lines ***
> 
> There is a workaround:
> 
> In the original /etc/avahi/avahi-daemon.conf file, there is an entry "#allow-
> interfaces=eth0".
> Changing and uncommenting it to "allow-interfaces=eth9" solves the problem
> (printer not conected via ethXYZ, though). 

"allow-interfaces=eth9" effectively prevents avahi-daemon from working
on all interfaces, including the loopback interface. ipp-usb is exposed
on the loopback interface by default.

avahi-daemon is now completely crippled; it may as well be purged from
the system.

>					 Therefor I assume this hides a bug
> or an improper default configuration.

There isn't any bug in avahi-daemon.

Regards,

Brian.