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

[Simon Matter]

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"
>>
>