[Pkg-cups-devel] CUPS USB backend URI <-> device mapping

[Roger Leigh]

Hi folks,

I'm planning to upload gutenprint-5.2.1 to unstable soon, and this new
upstream release removes the "canon" and "epson" CUPS backends
distributed with previous releases.

These backends added additional features for these manufacturers' printers,
such as ink level reporting via the backchannel.  They were capable of
driving parallel-, USB- and network socket-connected printers.  However,
the standard CUPS backends (parallel, usb, socket) now contain this
functionality, and the canon and epson backends have been removed.

In order to not break existing users' printer configurations, I've written
a small script incorporated into the postinst which will reconfigure the
device URI by determining which new backend to use:

http://git.debian.org/?p=collab-maint/gutenprint.git;a=blob;f=debian/cups-driver-gutenprint.postinst;h=3edeeb9e44ada953639a87e7e56f6be5fad68975;hb=3abe5f17325bd9e63384dadfea33061976c47583

While this will work for parallel devices, the CUPS USB backend no longer
works with plain device files, it wants a //MANFR/MODEL... syntax which
we can't predict.  As a result, this is broken for most USB printers--
the logic needs to be much more robust.

We can list the available devices with "lpinfo -v", but is there any way
of getting the real device node associated with each one, so that we can
upgrade the printer correctly?

Any other suggestions for how to do this, or notify the user to modify the
queue to correct it would be appreciated!  The above mechanism is also
dependent upon having the printer switched on to be picked up by the USB
backend, so can't always succeed in getting a device URI for a device node.


Thanks,
Roger

-- 
  .''`.  Roger Leigh
 : :' :  Debian GNU/Linux             http://people.debian.org/~rleigh/
 `. `'   Printing on GNU/Linux?       http://gutenprint.sourceforge.net/
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