Auto-creation of IPP network printer queues

[Brian Potkin <claremont102@gmail.com>]

I have an HP ENVY 4500 series inkjet. With cups-browsed 1.0.61-5 on
Jessie and 'CreateIPPPrinterQueues Yes' in cups-browsed.conf a print
queue is created. With cups-browsed 1.8.3-2 it is not. The output from
'cups-browsed -v' says it is ignoring this printer as "...its PDLs are
not known".

I eventually tracked this down to a change made in 1.3.0-1:

   cups-browsed: Auto-create queues for PCL-5c/e printers but
   not for HP inkjet printers (which also advertise themselves
   as PCL printers).

The TXT Record for this printer has

   pdl=application/vnd.hp-PCL,image/jpeg,application/PCLm,image/urf

so I assume it is 'application/vnd.hp-PCL' which is being discriminated
against.

It isn't the inability to auto-setup a queue which immediately concerns
me but it is the fact I do not know the basic reason why. The queue
would not be of much use to me anyway beause it only accepts PDF. What
is the significance of only accepting PCL-5c/e as a candidate PDL? The
concept of driverless printing is beginning to intrigue me.

I am in the process of writing a wiki page on AirPrint and, while I
could write reasonably confidently about what happens on Jessie,
extending my understanding can only help.

Possibly unrelated, but why does the GTK print dialog not display my
printer using its Bonjour broadcasts (no cupsd running)?

Thanks in advance for any insights.

Regards,

Brian.