[sane-devel] scanbd with Fujitsu fi-7260 Scanner: need help

[m. allan noah]

On Mon, Jun 9, 2025 at 2:34 PM Ralph Little <skelband at gmail.com> wrote:

> Hi,
>
> On Mon, Jun 9, 2025 at 11:27 AM m. allan noah <kitno455 at gmail.com> wrote:
>
>>
>> On Mon, Jun 9, 2025 at 12:11 PM Tricia via sane-devel <
>> sane-devel at alioth-lists.debian.net> wrote:
>>
>>> Hi, Dirk.
>>>
>>> On Mon, Jun 09, 2025 at 01:57:28AM -0700, Dirk Meier via sane-devel
>>> wrote:
>>>
>>> And here, we find that `scan` is now `1` (in technical terms, this means
>>> that _while checking_, scanbd found the scan button was being held down.
>>> It's possible to press the button so quickly that scanbd misses it while
>>> polling...)
>>
>>
>> A point of clarification here- the fujitsu backend attempts to buffer the
>> responses from the hardware and returns that buffered response so that
>> presses are not lost. But, if the frontend is slow enough in its polling
>> loop, I expect that could still happen. I'm not sure what the timing is for
>> scanbd
>>
>>
> Yeah, I have seem some machines capture button press events and latch them
> in software for the next query, while others only report button presses
> live. In the latter case, if you don't query while the button is being
> physically pressed, then you just don't see it at all. This is poor design
> I believe. It seems to me that it is unrealistic to expect that polling
> rate is sufficiently high for reliable detection necessarily. I would
> imagine that some Windows drivers are hammering USB ports at a fairly rapid
> rate to make this sufficiently responsive which is a bit crazy.
>

Fortunately, the Fujitsu (now Ricoh) hardware helps too, as it also buffers
button presses for a second or two, as long as you do not reset the
hardware. These are the sorts of features you get from quality equipment :)

allan
-- 
"well, I stand up next to a mountain- and I chop it down with the edge of
my hand"
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