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

[Simon Matter]

There is nothing in dmesg, unfortunately.
I see that the button daemon does a sane_open() but when it is terminated
with SIGTERM, there is no sane_close() called from what I understand.
Could that be problem?

Thanks,
Simon

> Again, check for kernel-level errors using dmesg.
>
> On Wed, Jan 14, 2026 at 2:59 PM Simon Matter <simon.matter at invoca.ch>
> wrote:
>
>> 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"
>> >
>>
>>
>>
>
> --
> "well, I stand up next to a mountain- and I chop it down with the edge of
> my hand"
>