Unable to reload SDDM

[ghost]

Describe the bug
When I switch video card, SDDM does not start, hangs on "Reaching graphical target". But after rebooting the system, the video card change is applied and works as expected. Is short I need to reboot OS to change card.

System info
Please include :
Operating System: Arch Linux
KDE Plasma Version: 5.15.0
KDE Frameworks Version: 5.55.0
Qt Version: 5.12.1
Kernel Version: 4.20.10-arch1-1-ARCH
OS Type: 64-bit
Processors: 8 × Intel® Core™ i7-8550U CPU @ 1.80GHz
Memory: 19,5 ГиБ

Logs

dmesg

Xorg

journalctl -u display-manager -b0 --no-pager
-- Logs begin at Mon 2019-02-18 21:06:12 EET, end at Tue 2019-02-19 15:22:37 EET. --
-- No entries --

journalctl -u optimus-manager -b0 --no-pager
-- Logs begin at Mon 2019-02-18 21:06:12 EET, end at Tue 2019-02-19 15:24:24 EET. --
фев 19 15:17:24 AcerAspire5 systemd[1]: Started Optimus Manager Commands Daemon.
фев 19 15:17:24 AcerAspire5 python[532]: Optimus Manager (Daemon) version 0.7.1
фев 19 15:17:24 AcerAspire5 python[532]: Awaiting commands

/etc/X11/ contains nothing related to GPUs except 10-optimus-manager.conf

[Shatur]

Partially fixed it by changing switching=nouveau to switching=bbswitch.
With this configuration, after changing the mode from Intel to Nvidia, I see the cursor and the message "Could not sync environment to dbus". And if I press the Ctrl + Alt + Backspace key combination (restart Xorg), the desktop environment starts up normally on the desired video card.
Here is my /var/log/Xorg.0.log for "Could not sync environment to dbus" error.

Also I have tried all this solitions.

[Askannz]

Do you have any issues if you boot directly in Nvidia mode ? (optimus-manager --set-startup nvidia)

To help me debug, please do the following with switching=bbswitch enabled :

• Boot into Intel mode
• Try to switch to nvidia mode and do that Ctrl + Alt + Backspace trick to recover the session
• Paste the log of the sddm service here (You can redirect it to a file like this : journalctl -u sddm -b0 --no-pager > /path/to/file.txt)

[Shatur]

Boot directly in Nvidia mode works.

Here is requested log :)

[Destroyerrrocket]

I can confirm this exact issue. If more logs are needed, I can also provide them.

[Askannz]

Sorry of the lack of updates. Could you test the current github master branch ?

[Destroyerrrocket]

I'll test it today and I'll update this comment.
EDIT: It works! The reported error: "Could not sync environment to dbus" is no longer present and I successfully enter the KDE plasma session without requiring any key combination trick. It also goes faster during the loading of the desktop and inside the desktop itself on both modes. no issues were encountered so far.
EDIT2: It still happens when reloading. The behaviour is the exact same one as the report. So far, this is the only issue. Booting from NVIDIA also still works.

[Shatur]

Yes, with the latest changes from the master branch everything works fine. Switching works both ways without any problems.

@Destroyerrrocket, what version of the kernel are you using? I tested on linux-lts.

[Destroyerrrocket]

@Shatur95 linux, I'll check linux-lts and update this comment. Could you also check if reloading works for you?
EDIT: For some reason, linux-lts does not cause the reloading error. Also, it doesn't seems to happen in all reloads on linux. I've managed to cause the error to happen once when I quickly reloaded the intel card when the desktop had just finished loading, but it is not a consistent error, so for the moment, thank you so much @Askannz for the info!

[Shatur]

@Destroyerrrocket, yes, linux work for me too :)