[sane-devel] Unstable scanning with Fujitsu fi-7160

[Simon Matter]

Everything changed, yes.
The button daemon is a quite small program so I expected it to work also
with the new system. I was wrong here and now I try to find out why it
leaves the system in a state where access to the device is blocked.

Simon

> What changed? Just the sane-backends version, or anything else (hardware,
> OS, etc)
>
> allan
>
> On Wed, Jan 14, 2026 at 2:32 PM Simon Matter <simon.matter at invoca.ch>
> wrote:
>
>> I can confirm now that the problem is with the button daemon
>> scanmonitord-sanebd only and not with scanimage.
>>
>> When I run "SANE_DEFAULT_DEVICE=fujitsu:fi-7160:42929
>> scanmonitord-sanebd"
>> several times in a terminal and terminate it with Ctrl+C, it will
>> suddenly
>> say "Open of device fujitsu:fi-7160:42929 failed: Invalid argument".
>> While studying the code of scanmonitord-sanebd.c I'm failing to
>> understand
>> what could be wrong. This has worked fine with SANE backends 1.0.24 but
>> something has changed here.
>>
>> If anyone has an idea what could be wrong, please let me know. I'm quite
>> lost here.
>>
>> Thanks,
>> Simon
>>
>> > I start to believe the problem is not in SANE itself but in the button
>> > daemon we are using (see attachement).
>> >
>> > Our software is running the button daemon and waits for events, then
>> > terminates the button daemon and does the appropriate scanimage job,
>> and
>> > then starts the button daemon again.
>> >
>> > The button daemon is a modified version of some daemon which was
>> floating
>> > around many years ago. It has worked well for the last 15 years or so.
>> > Maybe there is some modification needed to make it work well with
>> newer
>> > SANE.
>> >
>> > If someone who knows SANE better than me would take a look at it, that
>> > would be much appreciated.
>> >
>> > Thanks,
>> > Simon
>> >
>> >> We need to isolate the problem if possible- I expect if you compile
>> an
>> >> older, known working sane-backends on your current computer, the
>> problem
>> >> will persist. That would indicate hardware or OS level issue.
>> >>
>> >> allan
>> >>
>> >> On Wed, Jan 14, 2026 at 9:35 AM Simon Matter via sane-devel <
>> >> sane-devel at alioth-lists.debian.net> wrote:
>> >>
>> >>> >
>> >>> > Hello,
>> >>> >
>> >>> > On 2026-01-14 14:59, Simon Matter via sane-devel wrote:
>> >>> >> These scanners work perfectly fine with very old sane-backends
>> >>> >> and operating system.
>> >>> >
>> >>> > Does it work on the exact same computer
>> >>> > where it fails or does it work on old computers?
>> >>>
>> >>> It works fine on old computers with old software.
>> >>>
>> >>> >
>> >>> > I ask because of possible USB 3 related issues, see
>> >>> > https://en.opensuse.org/SDB:Configuring_Scanners#USB
>> >>>
>> >>> Thanks, I'll check it out.
>> >>>
>> >>> Simon
>> >>>
>> >>>
>> >>>
>> >>
>> >> --
>> >> "well, I stand up next to a mountain- and I chop it down with the
>> edge
>> >> of
>> >> my hand"
>> >>
>> >
>>
>>
>>
>
> --
> "well, I stand up next to a mountain- and I chop it down with the edge of
> my hand"
>