[sane-devel] Description file, Epson, and wildcards

Chris Bagwell chris at cnpbagwell.com
Tue Mar 2 00:55:21 UTC 2010

Hi all,

I'm reviewing Fedora patch set and notice an issue that I'm not sure
how to handle within Sane.  Has this been discussed in past?

It looks like all 3 Epson backends can detect SCSI scanners based on
scsi type being "processor", vendor ID being "EPSON", and the
model/product name having 1 of 5 prefixes.  This is good to know for
next step.

On Fedora, it seems its a common problem that hal or udev gets the
permissions for scsi Epson scanners wrong and users can only scan as
root.  They generically fix permissions for scsi "scanner" class but
not "processor".  Their work around is to edit entry for specific
scanner in the epson2.desc file and a line as follows each time a user
reports a problem:

:scsi "ESPON" "Exact Model Name Reported" "processor"

Once thats done, sane's tools will generate a
libsane.fdi/libsane.rules that will set permissions correct.  Sane is
not providing enough details right now it seems.  First option to help
end users is to start providing that much details.

Mostly, the epson2.desc values are driven by epkowa developers from
their epkowa.desc.  Would it be possible for epkowa developers to
provide a ":scsi" line for all SCSI devices?

Second option is to provide some kind of wild card support.  For example:

:scsi "EPSON" "Perfection*" "processor"

This would be pretty difficult to convert into hal and udev yntax
though. Its also will cause some confusion when a Perfection 636S rule
matches a Perfection 636.

A third option is to provide some sort of hard coded/hand written wild
card rules that is added to libsane.fdi and  libsane.rules for these
special cases.  This is probably the easiest.  It looks like at east
Epson and HP could benefit from this.

Do people think this is worth addressing?


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