[cups] USB quirk rules

[Michael Weghorn]

Hi,

by adding printers to the USB backend quirks file in CUPS, known issues 
when printing with CUPS on various USB printers can be worked around.

So far I was assuming (without actually knowing) that the underlying 
problems were bugs in the respective printer hardware (e.g. their 
firmware).

We recently received a new printer model where printing without adding a 
quirk rule had issues (and the issue was gone after adding a respective 
USB quirk rule). When addressing the issue to our supplier, we got got 
as a reply that the wrong behaviour was due to a wrong CUPS handling of 
USB printers and we should do the following to solve the issue:

     lpadmin -p <printername> -R usb-unidir-default
     lpadmin -p <printername> -o usb-no-reattach-default=true

This is basically what the USB quirk file does "automatically".

While adding a respective rule for a specific model is OK in a single 
case, I think it would be nice to have the underlying issue addressed to 
avoid that more or less the same problem reoccurs when a new model is 
introduced.

Is it possible to get more information on the underlying cause why such 
workarounds are needed and where a "proper" solution would have to be 
implemented (if possible at all)?

Regards,
Michael