[cups.general] Debugging the filter chain?

[Helge Blischke]

William Pietri wrote:

> I've got a Brother MFC-6490CW printer, which I'm connecting to via LPD.
> It works fine from my i386 Ubuntu system, but not my x86_64 Ubuntu box.
> I'm trying to figure out why.
> 
> Having turned on debug logging, I notice that when printing a test page
> the sad box says "Sending data file (0 bytes)". That certainly sounds
> like a problem, and my first hypothesis is that there's some issue
> rendering the test page to that printer.
> 
> I see in the logs that it starts a bunch of things (filters bannertops,
> pstopdf, pdftopdf, cpdftocps, and brlpdwrappermfc6490cw, and the lpd
> backend). Is there some easy way to me to peek into what's going on
> there in terms of inputs, arguments called, and outputs?
> 
> Worst case I figure I'll run strace, but I figure there must be some
> better magic for debugging issues like this.
> 
> Thanks,
> 
> William

I'd suggest to modify the /usr/share/cups/mime/*.convs to revert to the 
default PostScript oriented workflow instead of the PDF oriented workflow 
that the Ubuntu folks try to promote.
Thus, modify the .convs file(s) (by tweaking the cost values or commenting 
out the unwanted statements) such that the filter chain will read as:
bannertops -> pstops -> brlpdwrappermfc6490cw

You may send me the .convs file(s) if you think you need expicit help.

Helge