After install and rebooting the login screen shows a virtual keyboard

[Leó Kolbeinsson]

Testing Lubuntu Plucky daily ISO dated 17-12-2024

After install and rebooting the login screen shows a virtual keyboard - selecting the hardware keyboard works and am able to login as normal. Rebooting again and the virtual keyboard appears once more.

See attached screenshot

ProblemType: Bug
DistroRelease: Ubuntu 25.04
Package: sddm 0.21.0-6ubuntu1
ProcVersionSignature: Ubuntu 6.11.0-8.8-generic 6.11.0
Uname: Linux 6.11.0-8-generic x86_64
ApportVersion: 2.31.0-0ubuntu1
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: LXQt
Date: Tue Dec 17 18:12:10 2024
InstallationDate: Installed on 2024-12-17 (0 days ago)
InstallationMedia: Lubuntu 25.04 "Plucky Puffin" - Daily amd64 (20241217)
SourcePackage: sddm
UpgradeStatus: No upgrade log present (probably fresh install)

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/2091958

[Leó Kolbeinsson (leok)]

Screenshot

[Leó Kolbeinsson (leok)]

Further testing - Lubuntu Plucky daily ISO dated 26.01.2025

As in the original report - After install and rebooting the login screen shows a virtual keyboard - selecting the hardware keyboard works and am able to login as normal.

After logging in I then tried the following:
Opened "SDDM Configuration Editor" selected "General" and under "Input method module" entered "Keyboard"
and when logging out and/or rebooting the greeting screen appeared as in the attached screenshot.

This result was the same no matter what was entered in the "input method" box i.e tried several random letters etc. and same result on the login screen.

[ԜаӀtеr Ⅼарсһуnѕkі (wxl)]

This can be reproduced in the live environment. Here's how:
 1. When you get to the Try/Install screen, select Try Lubuntu to get to
the live environment.
 2. When in the live environment, logout.

At this point the SDDM login screen will be shown with the virtual
keyboard shown.

To get back into the live environment, click on the button to dismiss
the virtual keyboard (it's to the right of the space bar) and then hit
enter to login. This will get you back to the Try/Install screen. Click
Try Lubuntu.

Once back in the live environment, you can implement the solution: add
the following to /etc/sddm.conf:

[General]
InputMethod=

Yes, that's a null assignment. Anything other than the three valid
options results in the same effect: no input method (including no
virtual keyboard).

The three valid options (see `man sddm.conf`) are:
 1. qtvirtualkeyboard
 2. ibus
 3. compose

I think the only reason why the options you added didn't work is perhaps
because you didn't save the settings. I find that the SDDM Configuration
Editor is a little unintuitive, at least relative to a lot of other
dialogs we have. The two buttons at the bottom, in order, are:
 1. Save
 2. Close

The first time I tried to use it, I hit close. In the Shortcut Keys
dialog, this has the effect of saving the changes you made. I didn't
even notice save at first until I saw the changes I made had no effect,
especially after I had looked up what the valid options are.

There is another possible solution: uninstall
qt6-virtualkeyboard-plugin.

So now that gets us to why this happens. That's a little trickier.

Here's what I discovered in my research:
 * The manpage does not say what the default for InputMethod is. It does
suggest leaving it empty if unsure, which is to say it is suggesting
that an empty value has the effect of disabling all input methods.
 * Looking at the code, I can see that qtvirtualkeyboard is the default
value:
https://git.launchpad.net/ubuntu/+source/sddm/tree/src/common/Configuration.h#n48
 * This default value has existed since 0.17.0:
https://github.com/sddm/sddm/commit/ef7e0812dab3d2e56b2ad388e6c45ca5c84391d7
 * Of course that default value has no impact if the virtual keyboard
plugin isn't installed, which is why this probably hasn't affected us.
At that time, qtvirtualkeyboard-plugin was made a Suggests.
 * Late last year, after Oracular was released, qtvirtualkeyboard-plugin
was upgraded from a Suggests to a Recommends:
https://git.launchpad.net/ubuntu/+source/sddm/commit/?id=8c28b7475c8235204ec182865e7fac4d6064b2ea
 * Of course, we're on Qt6 now so I think it really didn't have an
impact until that was changed to qt6-virtualkeyboard-plugin.

It seems there's a valid reason to have this set up (make it easier for
tablets, as stated in the changelog), but it tends to be annoying,
albeit not insurmountable on desktops. I'm inclined to believe we should
probably keep this the way it is for better or for worse.

Should Lubuntu want to expressly change this, we would need to ship our
own sddm.conf.

[Leó Kolbeinsson (leok)]

@wxl Walter - thanks for the research and explanations- changing status to "invalid" as this is by design if I understood correctly - then this not a bug.

[ԜаӀtеr Ⅼарсһуnѕkі (wxl)]

Upon further consideration, I don't even know of a way to successfully install Lubuntu or any other Ubuntu flavor on a tablet. I'm questioning the plan to make tablets first class citizens.

That said, I think there's a safe approach to this: turn it off in a default config file.

[Launchpad Janitor (janitor)]

This bug was fixed in the package lubuntu-default-settings - 25.04.8

---------------
lubuntu-default-settings (25.04.8) plucky; urgency=medium

  * Add explicit configuration for SDDM.
  * Prohibit virtual keyboard on SDDM. (LP: #2091958)
  * Add explicit configuration for Picom. (LP: #2100464)
  * Remove Firefox from quicklaunch.
  * Add more sane defaults for fancymenu.
  * Populate favorites in fancymenu.

 -- Walter Lapchynski <email address hidden> Wed, 05 Mar 2025 02:54:39 +0000

[Leó Kolbeinsson (leok)]

Tested Lubuntu Plucky daily image dated 07-03-2025 and confirm fix - all good