I had a heck of a time figuring out why printing wasn't working on Fedora 26. It turns out that Qt applications have problems with CUPS printers that have ipp://... (or ipps://...) device-uri's. (This was a clean install, and I just happened to use ipp://... when I set up my printers; I had previously used http://...:631/....)
Symptoms include:
* Qt applications will default to "Print to File (PDF)," even though a default CUPS queue is set. (The CUPS printers are selectable in the drop-down, but ....)
* Page size will always default to A4, even if the printer is configured to use another default page size in CUPS.
* Most seriously, actually clicking on the "Print" button has no effect.
Gtk applications don't seem to have any problem with ipp[s] URLs, but running "lpoptions -l" will error out:
lpoptions: Unable to get PPD file for XXXXXXXXXX: Not Found
I suspect this is a symptom of this issue:
https://github.com/apple/cups/issues/4725
-
Ian Pilcher