[sane-standard] SANE 2 driver suggestion

[Donald Straney]

> The "hardware registration" suggested by Donald can easily be done
> via hald -- we only need to transform Sane's *desc files into *fdi
> files for hald. I have already tested this -- I mainly need to
> replace my prototype Python script that creates the fdi files with a
> patch/new output mode for sane-desc.c . I also played a bit with a
> hald callout for scanners; this callout can give some additional
> information.

Do you mean that to get a device list, sane_get_device_list would then
go through HAL?  That would work too, if you don't mind having the
Linux version rely on HAL (I was thinking of integrating it at a lower
level, but if this would work just as well and make it simpler then it
sounds good to me).

The problem with using only HAL rules to identify the scanners is that
parallel port and networked scanners won't show up.  I guess
sane_get_device_list could probe manually for parallel port scanners
and use Avahi or something similar to get remote computers running
saned on each call, but it would probably be better to get them into
the HAL device list somehow.  I'm guessing that automatically
detecting networked scanners with Avahi wouldn't be too hard, but
there's still the problem of parallel port devices.  Is there any way
around this, like running a quick SANE probe program at boot which
would test for non-hotpluggable devices and add them to HAL's device
list? (It would break if someone decides to hotplug their parallel
port scanner all the time, but does that really matter?)

Donald Straney