F36 xsane does not find HP scanner(s)

After upgrade from F35 to F36 xsane is not able to detect the multi-function printer/fax/scanner HP LaserJet M2727nf any more.
This is independent of whether I connect the scanner via LAN or via USB.
Typically it is connected via LAN with a fix local IP 192.168.xx.yy. USB connection was for test only.
The printer part is working, i.e. I can print on that device.
Re-installation of printer + fax via hp-setup and hp-plugin did not help.
Another computer in the same network still running F35 is detecting the identical M2727nf scanner and scanning works from there.
Another scanner, a Fujitsu fi-7240 connected via USB is detected by xsane, before and after migration to F36.
Same situation with F36 but a differnt HP scanner in another location connected via VPN.

Any hints on what to do / how to investigate further are very welcome!

This is very typical and something to always be aware of with HP MFPs. The scanner in the printer requires a proprietary plugin for hplip that matches the hplip version.

With the default hplip installation on fedora you can run hp-plugin and install the scanner plugin.
If you have installed hplip-gui (available from the fedora repo) then you can also use the HPLIP Graphical Tools gui and select to install/update the plugin there.

With every version update of hplip you will have to update the plugin to match. Just one thing to be aware of when Sane complains like that.

Thanks for your hints, Jeff!
I typically run hp-plugin manually as you described to get printer and scanner working again. This is necessary quite frequently after Fedora updates.
(I still do not know what kind of updates really break the printer / scanner functionality, but this is another topic.)
This time however, it does not help for the scanner to be detected again.

hp-plugin

executed using all defaults as always, executes nicely and completely

HP Linux Imaging and Printing System (ver. 3.22.2)
Plugin Download and Install Utility ver. 2.1
[...]
Do you accept the license terms for the plug-in (y=yes*, n=no, q=quit) ? 
Done.
Done.

But still:

hp-scan

results in

HP Linux Imaging and Printing System (ver. 3.22.2)
Scan Utility ver. 2.2
Copyright (c) [...]
error: No device selected/specified or that supports this functionality.

Is there a chance other than waiting for HP to provide something better?
Could the root cause be on Fedora side?

What hplip packages are installed? dnf list installed hplip* libsane-hpaio

You should see at least hplip and libsane-hpaio (and possibly hplip-gui) in that output. If not then you should install those missing packages. Libsane-hpaio is required (in addition to the plugin) for sane to access the hp MFP scanner.

How did you define the printer? Did you use the HP tools or did you allow avahi to automatically define it?
I have had issues with printing when avahi defines it since that definition does not use the HP driver.

You have commented on other scanners and other systems, but it is unclear if this particular system has been able to use this scanner before or not.

1 Like

Jeff, you are the best!

libsane-hpaio had been missing, so

dnf install libsane-hpaio

fixes the problem.
Meanwhile I tracked down the problem:

  1. libsane-hpaio had been installed in F35, so everything was working
  2. libsane-hpaio also was updated to the F36 “version” with the global update F35 to F36. To be more precise:
    libsane-hpaio.x86_64 3.22.2-1.fc35 was updated to
    libsane-hpaio.x86_64 3.22.2-1.fc36
  3. After the update I ran
dnf autoremove

and this removed libsane-hpaio!
And resulted in scanning no more possible, because xsane not being able to find the scanner.

My best guess is that a dependency is missing since F36.
Because in the past it never was a problem for the scanner to do “dnf autoremove”.
If you have the chance to address this to the right people at the right place this could be helpfull for quite a few people.

To anyhow answer some more of your questions:
The printers in my office here are HP M2727nf and HP M283fdw, both now are detected again by both computers, one still running F35 and the other computer running F36 already.
The printer in the remote office is a HP CM2320nf, also now detected again by both computers there both running F36.
All printers/scanners now are available to all computers again as before, via VPN.
(Some combinations of computer + printer/scanner are not needed, so not installed via hp-setup, but my main computer used for sys admin jobs has them all.)

This is my well-working setup, to give the complete picture:

dnf list installed hplip* libsane-hpaio
Installierte Pakete
hplip.x86_64          3.22.2-2.fc36   @fedora
hplip-common.x86_64   3.22.2-2.fc36   @fedora
hplip-gui.x86_64      3.22.2-2.fc36   @fedora
hplip-libs.x86_64     3.22.2-2.fc36   @fedora
libsane-hpaio.x86_64  3.22.2-2.fc36   @fedora

Thanks a lot again!

Glad I was able to help.
I never use dnf autoremove, and if I did I would be sure to verify what it was removing before I said yes.

Just need to keep in mind that on the HP side it requires the plugin and on the Sane side it requires libsane-hpaio