Frederik Ramm wrote:
>
> Hi,
>
> my scanner has a "scan" button that (at least using their Windows
> driver) can be used to launch certain programs on the host system.
>
> I've written something similar for the SANE environment. It's called
> "sensed" and works by sending a SCSI "REQUEST SENSE" command to the
> scanner in regular intervals (every 2 sec). If the response indicates
> that the scan button has been pressed, a program is launched. (This
> would usually mean scanadf or scanimage, maybe called by a shell
> script that stores the results away properly.)
>
> The current, initial version is very crude, has only been tested with
> my Fujitsu M3091DCd scanner, and it doesn't even have a Makefile etc.
> (it relies on the SANE SCSI core so you'll have to stuff it into the
> "backend" directory, compile and link with libsanei.a).
>
> It's here: http://www.remote.org/frederik/projects/software/sane/
>
> Feel free to play with it. If anyone's willing to help me make this a
> proper part of SANE, including it in the "tools" directory, putting it
> in CVS and tweaking the Makefiles accordingly, you're most welcome.
> But perhaps that should wait for a version that is more configurable
> and supports more scanners.
>
> For the SCSI gurus out there, is there any potential disruption by
> sending REQUEST SENSE to a device every two seconds? I noticed that
> while someone has "grabbed" the device, the call blocks anyway (which
> doesn't hurt my program). sensed does not attempt to grab and release
> the device; should it?
Frederik,
Two minor two problems might occur:
1. Older versions of the Linux aha152x driver refused to accept a
REQUEST SENSE command. This is fixed in recent versions; I don't know,
if other adapter driver have similar restrictions.
2. sanei_scsi_open opens the device file O_EXCL. So, if a frontend is
started independently from you daemon, this call might fail, if this
call happens, while your daemon is accessing the scanner.
Abel
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This archive was generated by hypermail 2b29 : Thu Mar 08 2001 - 14:40:23 PST