https://bugs.kde.org/show_bug.cgi?id=502746
Junak <[email protected]> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |[email protected] --- Comment #9 from Junak <[email protected]> --- I believe I found the root cause of this. It is in the KCM helper, not in the plymouth-themes package. Reproduced on Kubuntu 26.04.1 LTS with kde-config-plymouth 6.6.4. Cause `PlymouthHelper::save()` in `src/helper.cpp` handles Ubuntu-based systems through update-alternatives: - If the chosen theme's `.plymouth` file is not yet registered in `update-alternatives --list default.plymouth`, the helper only runs `update-alternatives --install /usr/share/plymouth/themes/default.plymouth default.plymouth <file> 100` and skips `--set` (it is an `if/else`). - Only if the file is already registered does it run `update-alternatives --set default.plymouth <file>`. `--install` does not change the selected alternative when the group is in manual mode, or in auto mode when another alternative has a higher priority. Kubuntu's `kubuntu-logo` uses priority 150, for example. Ubuntu's initramfs hook (`/usr/share/initramfs-tools/hooks/plymouth`, line 22) takes the theme from the `default.plymouth` alternative, not from `plymouthd.conf`. So `update-initramfs -u` packs the previous theme, and the old splash is shown after reboot. At the same time, the helper writes `Theme=<new>` to `/etc/plymouth/plymouthd.conf`, so the KCM shows the new theme as the current one. Applying the same theme again doesn't help, because Apply stays disabled. A theme that is already registered (for example after a second attempt via another theme and back) takes the `--set` branch and works. That is why the problem looks random. About the plymouth-themes hypothesis: its postinst registers only `spinner` (default.plymouth, priority 70) and `text` (text.plymouth). Themes like `tribar` or `details` stay unregistered, so they hit the `--install`-only path. Steps to reproduce 1. Pick a theme whose `.plymouth` is not listed by `update-alternatives --list default.plymouth`, e.g. `tribar`, `details`, or a theme installed via "Get New…". 2. Apply. 3. `update-alternatives --query default.plymouth` still shows the previous value, and the previous splash appears after reboot. `/etc/plymouth/plymouthd.conf` contains the new `Theme=`. Suggested fix Run `update-alternatives --set default.plymouth <file>` in both branches, i.e. also after `updateAlternativesInstall()`. Workaround sudo update-alternatives --set default.plymouth /usr/share/plymouth/themes/<theme>/<theme>.plymouth sudo update-initramfs -u Related: bug 399901. The KCM determines the current theme only from `Theme=` in `plymouthd.conf` (`kcm.cpp`, `load()`), while on Ubuntu the active theme is the alternative. After a plymouth package upgrade replaced `plymouthd.conf` (the old one went to `.dpkg-old`), the KCM highlighted the wrong theme here. Kubuntu 26.04.1 LTS · kde-config-plymouth 6.6.4 · plymouth 24.004.60+git20250831.4a3c171d-0ubuntu8 -- You are receiving this mail because: You are watching all bug changes.
