Axios I got it on good authority I make these threads to big...lol
I've been told the same thing!
it's coming from a good place though. people need their stuff to work and if you can point 'em in the right direction that's the best. linux is far from windows with some stuff but that's its charm
Just tested the fix in unstable, it is working. Nice 
️
This is good news. 
So I'm waiting for this patch to be upgraded to stable to confirm that the problem is now resolved and close this post.
PS. You will have to be a little patient, @EbonJaeger in his last post not predicting new Solus updates before week 13.
In the meantime, thanks to all those who helped achieve this fine result, and in particular to @TraceyC and @alfisya . 
Thanks. Happy to help peoples' lives be a little less stressful, at least in regards to their hardware.
After treatment of Solus updates for week 13, I can confirm that simple-scan behaves again as before its update of 02/16/2024, i.e. that the scanning of several pages in a single PDF document is possible.
However, I noticed a curious thing:
Anyway, in the current state of things, it is still satisfactory, because it's important to have an application that can scan multiple pages in the same document, in particular for administrative procedures.
And thank you for your responsiveness and efficiency.
penny-farthing on the other hand, when we select "Multiple pages from a flat scanner" (multiple pages from a flat scanner), after scanning of each page appears this error message "impossible to start scanning" (unable to start scanning) that you just have to validate and then scan the next page, which is rather a curious behavior.
I just tried this with my HP all-in-one and was did not see any error. I scanned multiple pages from the flatbed with that option.
Something you can try is to run
`hp-plugin'
Does it tell you that the driver plugin for HPLIP 3.23.12 is already installed?
If it isn't, go ahead and install it.
If the plugin is already installed, the problem is an upstream bug, unfortunately. You can search the HPLIP bug tracker to see if there is an issue that matches yours.
If the problem only happens with Simple Scan, and not other software, it may be a bug in Simple Scan.
You might try running it in debug mode, see the instructions here.
You could also look through the simple-scan issue tracker. This issue looks similar.
I just did a reinstall of Solus 4.5 Gnome last week and have an Officejet Pro 6978. I installed hplip using the repositories (after switching to xorg) and then ran hp-setup. I had some problems with connecting to the printer but ran hp-plugin and the problems were fixed.
To make a long story short, the app in the repositories called "document scanner" works perfectly for me. I was able to scan multiple page documents double sided from the tray with no problems.
I get an error running hp-setup in wayland but everything is good after I install in xorg and move back to wayland.
I don't know f any of this is relevant, but it is my experience.
So, I've installed hp-plugin and whether it is immediately after installation or after reboot, the situation remains unchanged when simple-scan uses the option "Pages multiples depuis un numériseur à plat" (multiple pages from a flat scanner), the error message "Impossible de démarrer la numérisation" (impossible to start scanning) after scanning of each page.
However, the latest Solus update means that we no longer get blocked on the first page scanned, which is already satisfying.
NB. The software Skanpage no longer produces any error message since this last update Solus.
Below, the result of a simple-scan use test in debug mode (I scanned a page 3 times to enter the same PDF document):
https://0.0g.gg/?acbf6827ab72ea01#GLmbEwwAdejWcjXaGHFhNU55eMzZt7sXt4xEW2CG1o1d
I remain at your disposal.
penny-farthing Below, the result of a simple-scan use test in debug mode (I scanned a page 3 times to enter the same PDF document):
Thanks for the debug info. I assume you were using "Pages multiples depuis un numériseur à plat" for this. It seems like there were 3 successful page scans.
The most useful information I see from it is this:
[+36,44s] DEBUG: scanner.vala:1475: sane_read (22950) -> (SANE_STATUS_GOOD, 7649)
[+36,44s] DEBUG: scanner.vala:1475: sane_read (22951) -> (SANE_STATUS_EOF, 0)
[+36,44s] DEBUG: scanner.vala:1352: sane_start (page=1, pass=0) -> SANE_STATUS_INVAL
[+36,44s] WARNING: scanner.vala:1379: Unable to start device: Invalid argumentIt seems like Document Scanner had trouble communicating with the SANE scanning back end. I would recommend asking about this on the simple-scan issue tracker, as I mentioned. This looks like the root cause is in Simple Scan.
I suppose that you gave me this link to create a new issue:
https://gitlab.gnome.org/GNOME/simple-scan/-/issues
But, to do this, I must create a new account.
When I validate its creation, I get the following message: "1 error prohibited this user from being saved: Email is not allowed for sign-up. Please use your regular email address. Check with your administrator."
In the Email field, it says: "We recommend a work email address." I don't have a work email address, only a personal one.
How do I proceed?
Thank you in advance for your feedback.
penny-farthing
Unfortunately, I'm not familiar with the procedures for that website. I do see that on the registration page you can use a number of different accounts, such as Google, GitHub, etc. For further assistance, please follow the support instructions on the registration page.
My GitLab account is created since today.
So, I create this issue below:
https://gitlab.gnome.org/GNOME/simple-scan/-/issues/394
I remain at your disposal.