Failed to start SDDM

Support Graphics & Display
,
21

Do you have inside the ~/.xinitrc
the line
DEFAULT_SESSION=startplasma-x11
and at the end something like
exec $(get_session)
or
exec startplasma-x11
?

To me that coredump from sddm is a sign of partial update to be honest, but if you say the system worked just with video-linux then try that again.
Share then the proper inxi -Fxza --no-host (without the OCR thing, but from withing the installed system) and try some ACPI kernel boot parameters as mentioned in the other link.

22

Easiest option would to be to fresh install once again. once you get GUI install video-linux then Hybrid amd-nvidia driver then do reboot. I don’t whether video-modesetting is required or not.

23

So I did a fresh installation and it’s working now . But I did notice an error while booting that says:

[FAILED] Failed to start Load/Save Screen Backlight Brightness of backlight:acpi_video0

So after I got to the GUI I checked the backlight status with

systemctl status systemd-backlight@backlight:acpi_video0.service

and here is the log:

● systemd-backlight@backlight:acpi_video0.service - Load/Save Screen Backlight Brightness of backlight:acpi_video0
     Loaded: loaded (/usr/lib/systemd/system/systemd-backlight@.service; static; vendor preset: disabled)
     Active: failed (Result: exit-code) since Tue 2020-09-08 13:08:02 IST; 14min ago
       Docs: man:systemd-backlight@.service(8)
    Process: 831 ExecStart=/usr/lib/systemd/systemd-backlight load backlight:acpi_video0 (code=exited, status=1/FAILURE)
   Main PID: 831 (code=exited, status=1/FAILURE)

Sep 08 13:08:02 rocktim systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:acpi_video0...
Sep 08 13:08:02 rocktim systemd-backlight[831]: Failed to get backlight or LED device 'backlight:acpi_video0': No such device
Sep 08 13:08:02 rocktim systemd[1]: systemd-backlight@backlight:acpi_video0.service: Main process exited, code=exited, status=1/FAILURE
Sep 08 13:08:02 rocktim systemd[1]: systemd-backlight@backlight:acpi_video0.service: Failed with result 'exit-code'.
Sep 08 13:08:02 rocktim systemd[1]: Failed to start Load/Save Screen Backlight Brightness of backlight:acpi_video0.

I also looked for the journal entry for that specific PID with

journalctl -b _PID=831

and it outputs:

-- Logs begin at Tue 2020-09-08 13:08:01 IST, end at Tue 2020-09-08 13:31:50 IST. --
Sep 08 13:08:02 rocktim systemd-backlight[831]: Failed to get backlight or LED device 'backlight:acpi_video0': No such device

[ps: It’s just a warning wheen booting everytime, But it’s not stopping the booting process, Still I would like to know what’s up]

24

Disable it:
sudo systemctl disable systemd-backlight@.service

25

It’s still there :confused:

26

You have to reboot.

27

I did reboot . It fixed the issue of default maximum brightness after a boot but the actual error still shows up.

I am going through an online thread where this guy fixes this same issue by

I just added acpi_backlight=vendor to the arguments of the kernel and everything seems to work now!
/etc/default/grub:

GRUB_CMDLINE_LINUX_DEFAULT="quiet acpi_backlight=vendor"

But this thread is from an archlinux forum so I am not sure If I should touch the grub config file after all I’ve been through

28

You can test it from Grub Boot Menu, you add it, test it, and if is not working you drop the ideea to add it permanently to grub. If works, then is perfectly fine to add it, then run sudo update-grub and nex reboot will take effect automatically.

29