Re: Sddm cannot find breeze theme

On Fri, Jun 13, 2025 at 8:58 AM sicarine <
[email protected]> wrote:

> (Snipped previous messages for for length)
>
> I wanted to give an update on this in case someone searches the mailing
> list archives in the future.
>
> In the last build, I resolved issues with the sddm greeter by symlinking.
>
> I rebuilt BLFS from scratch on a much faster computer.
> This time I went strictly by the book using /opt/kf6 and
> /opt/qt6 as prefixes. I still ran into the same issue of missing breeze
> components. So I wanted to find a better solution as I understand
> that in some cases symlinks generally mask a deeper configuration
> issue without fundamentally addressing the problem.
>
> Looking at the git repository for sddm, I think I found that the
> fundamental issue is that sddm appears to use its own environment
> variables, and so either does not check /etc/profile, or doesn't
> understand BLFS's added pathappend function (or both).
>
> However, /etc/sddm.conf does also allow you to manually set the
> greeter's environment variables, and so I was able to manually set
> $PATH, $XDG_DATA_DIRS, $XDG_CONFIG_DIRS, $QML2_IMPORT_PATH,
> and $QT_PLUGIN_PATH.
>
> One symlink seemed to be requited, linking /opt/qt6/include/Plasma
> to /usr/include/Plasma.
>
> That seemed to fix most of the greeter's issues.
>
> I am, however, still trying to hunt down why the greeter lacks permissions
> to allow me to sleep/restart/poweroff, and it's taking a while to
> narrow down since most resources assume one is using systemd.
>
> Being new at this, I still cannot rule out that I've made some dumb
> error on my part twice, however one bug I found with the blfs book is
> in the sddm-0.21.0 instruction:
>
> >In order to see the theme without leaving the session, issue:
> >sddm-greeter --test-mode --theme <theme path>
>
> I believe "sddm-greeter" should be "sddm-greeter-qt6" in a QT6-only build
> like BLFS.
>
> Cheers,
> Sicarine
> --
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>

Thank you for this update. It fits my experience using the 12.3 BLFS
guidance with the goal of getting KDE/Plasma/Wayland running.
Initially I could get KDE Apps like Kate, Dolphin, and Konsole working only
under TWM and Xorg. In this environment if I clicked on a text file in
Dolphin, the
context menu offered me the option to launch a Kate edit session of the
text. While this worked the Xorg logon window recorded that each of the 3
functions defined in the BLFS, path_append, prepend,etc. were reported as
invalid and ignored by kio. In this case however the Kate edit sessions
worked. I could never determine what problem was under this behavior. This
might be a clue for others since it seems to duplicate the messages you got
in the context of SDDM analysis.

When I moved on to SDDM with some symlinks as you had suggested, I was able
to get SDDM working with XWayland, but there were a number of problems in
that environment. In particular, an obvious one was that the KDE Help
center, aka plasma-welcome, was broken on one of its panels and the panel
displayed the info that the FORM: AboutKDEHelp was not defined. This is the
QML Form that was needed for this particular panel of the plasma-welcome
app.

I have had lots of experience with other graphical UI systems over my
career, but retired when QT5 was just becoming popular. So I had to take a
while to educate myself on Qt6 and the QML portion of it. Early this week I
realized that the missing QML Form was added in Kirigami-addons.1.5 in
October 2024, and was a requirement for at least this one portion of
Plasma. The version recommended in the 12.3 BLFS book is Kirigami-addons
1.4. Fetching the update to Kirigami-addons, and building it completely
cured the problem with plasma-welcome.  I have not yet attempted to rebuild
other parts of the KF6 or Plasma files to see of this fixes anything else.
I will note that the current dev version of the BLFS book seems to have
gone on to Kirigami-addons 1.7, So this specific problem should not appear
for anyone using more recent versions of the dev BLFS book.

At this time all my attempts and research have failed to explain why I
cannot get SDDM to logon a user in the Plasma/Wayland mode. I was able to
find several log files that suggested that I needed something like the
QML2_IMPORT_PATH and others that you mentioned. Whenever I attempt to logon
in this mode, the screen goes black and logs show that there is a failure
regarding one or more of these symbols utilized by SDDM. SDDM always goes
back to the greeter/logon screen. I had given up on solving this problem
until I saw today's post. I had not yet thought to explore the sddm.conf
file in my environment.

Thanks again, and please post what you can about the specific contents that
you added to the sddm.conf file to get to your success. Please confirm, if
you can, that you are now able to logon from SDDM in Plasma/Wayland mode as
well as XWayland.

In a related question to the LFS team, can you share any target date you
have for the next stable BLFS systemd release? I would like to update my
homebrew linux system, but would rather wait until you think BLFS is stable.

-Dave-

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