[sane-devel] GT68XX Plustek OpticSlim 2600 Support

[Ralph Little]

Hi,

On Mon, Dec 30, 2024 at 11:25 AM Michal Waligora <michalwaligora62 at proton.me>
wrote:

> Hi,
>
> I’m extremely pleased to say that I got the Plustek OpticSlim 2600 working
> just fine!
>

That's great to hear!


>
> Sadly, calibration failed completely, even with the GT68XX_FLAG_OFFSET_INV
> flag. I traced back the “setting AFE reached limit” error message to the
> relevant source code and saw that the GT68XX_FLAG_NO_CALIBRATE flag, which
> isn’t mentioned on the adding page, disabled a block of code responsible
> for calibrating. The scanner works with the flag only.
>
> I am unsure why the calibration is broken. Is the existing GT68XX driver
> somehow slightly incompatible with the OpticSlim 2600, or could it be
> caused by hardware damage (although the scanner looks fine)?
>

It may be that calibration is highly scanner specific or at least
paramaterized in ways that the backend cannot yet handle.
Unfortunately IFAICS, these chips do not have public programming
instructions so I suspect that the backend has been composed largely of
replicating captures and inference.
I do now have 1 or 2 of these scanners and started to look at the code
recently. It is probably low on my list of stuff to do though. :(


> Next, multiple manuals I found online suggest that the output color depth
> should be 48-bit, but compiling with anything more than {12, 8, 0} and {12,
> 8, 0} gave an error about invalid arguments (I think) at runtime. I tested
> DPIs from 300 to 2400, and they all worked.
>
> Please let me know if you would like this upstreamed. I’m more than happy
> to help contribute it on Gitlab.
>

Yes, certainly. Let us not lose the work you have done.
Probably the best thing would be to create an issue on gitlab here:
https://gitlab.com/sane-project/backends/-/issues and add what you have
found with any code fragments that you think pertinent.

Thanks again for your efforts.

Cheers,
Ralph
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