[sane-devel] Re: [PATCH] generate hal fdi file

[m. allan noah]

of course, now that i think about it, this idea has the same problem
of device ownership/locking. i suppose you could change every backend
to lock open devices (plustek does this already?), and every front-end
would have to send/accept signals based on lock ownership? sounds
ugly...

allan

On 3/20/07, m. allan noah <kitno455 at gmail.com> wrote:
> On 3/20/07, Étienne Bersac <bersace03 at laposte.net> wrote:
> > Hi allan,
> >
> > > it would be nice if some of the linux gnome devels would engage in
> > > SANE discussions on the SANE lists. they might learn something about
> > > the hardware they are trying to support :) button handling comes up
> > > here quite a bit, you should search the archives of the sane-devel and
> > > sane-standard mailing lists.
> >
> > You know i'm contributing to this list. The discussion on Gnome derived
> > to SANE and thus, land here. Don't threat a Gnome devels complot ;P
>
> just trying to make sure you guys were paying attention :)
>
> >
> > > 1. you need a piece of code that understands the button-reading
> > > protocol for every scanner that sane supports. you will end up
> > > replicating a fair bit of code that is already (hopefully) in
> > > sane-backends, esp. for devices that require a bit of initialization
> > > before they can communicate.
> >
> > ACK. I really don't want to have "buttons monitor backends" and
> > "acquisition backends". That's crazy to maintain. The HAL add-on will
> > use SANE and provide two dbus method (e.g. Reclaim and Release) in order
> > to transmit device ownership.
> >
> > > 2. what happens when the user fires up scanimage command line tool
> > > without pressing any buttons? how do we deal with the contention for
> > > the device?
> >
> > Don't use HAL :).
> >
>
> so now every linux distro that enables HAL support in SANE, locks
> their users out of the most commonly used frontend, just to get button
> support?
>
> i would rather see a more general, non-linux specific method of
> handling buttons. how about a daemon that runs, gets the sane device
> list in the normal way, and then monitors each of the found devices
> for button presses as regular sane options.
>
> when a press is found, and there is a configured event to run, it
> sane_close() that device and fork/exec another frontend, passing it
> the device name as an arg. when the child exits, the daemon could
> regrab?
>
> on linux, sane_get_devices and other such functions might have the
> ability to use a more advanced device finding capability?
>
> allan
>
> --
> "The truth is an offense, but not a sin"
>


-- 
"The truth is an offense, but not a sin"