[sane-devel] Disable unsupported devices in udev libsane.rules?

Johannes Meixner jsmeix at suse.de
Tue Feb 3 08:56:53 UTC 2009


On Feb 3 11:23 Olaf Meeuwissen wrote (shortened):
> "m. allan noah" <kitno455 at gmail.com> writes:
>> On Thu, Jan 29, 2009 at 10:27 AM, Johannes Meixner <jsmeix at suse.de> wrote:
>>> I like to suggest to disable those entries in the
>>> udev rules file which belong to unsupported devices
>>> (at least for devices which are no "usual" scanners).
>> Personally, I would like to see those type of machines dropped from
>> the .desc files, particularly when the linked site says SANE support
>> won't happen, and external progs should be used instead. For a machine
>> that is a true 'scanner', and might be supported with a simple code
>> change, I think it still makes sense to still ship the rules.

I think even if SANE support won't happen but when it is a device
that is a true 'scanner', it should be listed in the .desc files
to have the user informed.

But I think that a device which is no true 'scanner' should not be
listed in a .desc file (i.e. a device which is outside the scope
of the SANE project).

> I had a look at the Novell Bugzilla and it sure looks that this comes
> from our epkowa.desc.  A long while back I basically added any Epson
> scanner out there I could find based on the idea that the backend in
> fact supports the bigger part of them, even if some may not have been
> tested.  I tried to provide as much information as I could possibly
> find so people would be able to search for their device and see what's
> up or where they could find more info.

I appreciate it to have as much information available as possible.
I think the more information is provided to the user the better.
In particular to avoid confusion which is often caused
when unexperienced users tell other users stuff like
"Epson scanners work perfectly with epkowa", then it is
really good to have exact information in epkowa.desc like 
Stylus CX-5800
Probably unsupported at the moment.
Not compatible to snapscan backend.
It's not known if it may work with epson or epkowa backend.
Perfection 660
unsupported [by the epkowa backend]
supported by the snapscan backend

> The changes you suggest seem to indicate removing this information,
> whereas Johannes is merely asking for sane-desc to stop outputting
> udev/hal rules for unsupported devices.

I would even output a udev/hal rule which is disabled
(i.e. as a comment in the the udev/hal files) so that
it would be easy for the user to enable it if needed.

> I like the latter approach
> better by a lot.  Whatever info is available will still be visible on
> the SANE web pages but udev/hal will no longer recognise the device as
> a scanner (unless supported by another backend).
> That is to say, the problem is with sane-desc, not in the .desc files.
> If I understood what the code does correctly the attached patch should
> fix it.

Many thanks for the patch!

Kind Regards
Johannes Meixner
SUSE LINUX Products GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany
AG Nuernberg, HRB 16746, GF: Markus Rex

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