Bug 473144 - Kernel 6.2: Logout ends up to a black screen - cannot switch TTY
Summary: Kernel 6.2: Logout ends up to a black screen - cannot switch TTY
Status: RESOLVED UPSTREAM
Alias: None
Product: neon
Classification: KDE Neon
Component: general (show other bugs)
Version: unspecified
Platform: Neon Linux
: NOR normal
Target Milestone: ---
Assignee: Neon Bugs
URL: https://bugs.launchpad.net/ubuntu/+so...
Keywords:
Depends on:
Blocks:
 
Reported: 2023-08-08 11:19 UTC by Lassi Väätämöinen
Modified: 2023-08-09 14:23 UTC (History)
4 users (show)

See Also:
Latest Commit:
Version Fixed In:


Attachments
Journalctl output for kernel 6.2 and 5.19 (1.59 MB, application/octet-stream)
2023-08-08 14:28 UTC, Lassi Väätämöinen
Details

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Description Lassi Väätämöinen 2023-08-08 11:19:29 UTC
SUMMARY
When logging out of KDE Plasma session, the screen ends up black, with the TTY cursor in upper left corner. Cannot switch TTY, but can reboot with Alt + SysRq + REISUB -sequence

STEPS TO REPRODUCE
1. Login to Plasma X11 session
2. logout

OBSERVED RESULT
Black screen shown. Waiting does not help.


EXPECTED RESULT
SDDM login greeter should get shown.

SOFTWARE/OS VERSIONS
Operating System: KDE neon 5.27
KDE Plasma Version: 5.27.7
KDE Frameworks Version: 5.108.0
Qt Version: 5.15.10
Kernel Version: 6.2.0-26-generic (64-bit)
Graphics Platform: X11
Processors: 16 × 11th Gen Intel® Core™ i7-11850H @ 2.50GHz
Memory: 46,7 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics
Manufacturer: LENOVO
Product Name: 20YRS21300
System Version: ThinkPad P15 Gen 2i


ADDITIONAL INFORMATION
- 'Reboot' and 'Shutdown' options from Plasma X11 session work OK.
- I cannot see anything relevant in journalctl for SDDM, but it only shows successful login, but no logout info.

- .xsession-errors shows:

> kdeinit5_wrapper: Warning: connect(/run/user/1000/kdeinit5__0) failed: : No such file or directory
> Error: Can not contact kdeinit5!
Comment 1 Lassi Väätämöinen 2023-08-08 11:57:35 UTC
Same thing happens when doing "Switch user" from the lock screen.

So, anything that requires re-displaying SDDM does not work: logout and switch users. But shutdown and reboot work.
Comment 2 Lassi Väätämöinen 2023-08-08 12:53:25 UTC
SDDM version: 
0.20.0-0xneon+22.04+jammy+release+build27
Comment 3 Lassi Väätämöinen 2023-08-08 13:03:26 UTC
(In reply to Lassi Väätämöinen from comment #2)
> SDDM version: 
> 0.20.0-0xneon+22.04+jammy+release+build27

Tried also downgrading to SDDM 0.19.0-4+22.04+jammy+release+build24, but same issue.
Comment 4 Lassi Väätämöinen 2023-08-08 13:13:02 UTC
Could this be related? From syslog:

elo 08 11:58:12 mopo sddm[1113]: Authentication error: SDDM::Auth::ERROR_INTERNAL "Process crashed"
elo 08 11:58:12 mopo sddm[1113]: Auth: sddm-helper (--socket /tmp/sddm-auth-a73f10ef-150c-492a-8686-1f364ff8b4a8 --id 1 --start /usr/bin/startplasma-x11 --user vaatala) crashed (exit code 1)
elo 08 11:58:12 mopo sddm[1113]: Authentication error: SDDM::Auth::ERROR_INTERNAL "Process crashed"
elo 08 11:58:12 mopo sddm[1113]: Auth: sddm-helper exited with 1
elo 08 11:58:12 mopo sddm[1113]: Signal received: SIGTERM
Comment 5 Lassi Väätämöinen 2023-08-08 13:55:49 UTC
Looks like possible KDE Neon kernel issue. I rebooted with  the previous kernel, and logout works fine:
5.19.0-46-generic

The issue happens with
6.2.0-26-generic
Comment 6 Lassi Väätämöinen 2023-08-08 14:28:03 UTC
Created attachment 160835 [details]
Journalctl output for kernel 6.2 and 5.19
Comment 7 Lassi Väätämöinen 2023-08-09 13:43:30 UTC
I wonder could it be related to this linux-firmware issue with NVIDIA Turing arch:
https://gitlab.freedesktop.org/drm/nouveau/-/issues/207
https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/commit/?id=2e92a49f90f73c8edc44b25c6e669d5e70893c90

Current linux-firmware package in Jammy is:
20220329.git681281e4-0ubuntu3.17

So that would be slightly older than the one where the NVIDIA fix was introduced (3rd April)
Comment 8 Lassi Väätämöinen 2023-08-09 13:54:53 UTC
https://gitlab.freedesktop.org/drm/nouveau/-/issues/207
>Versions with this issue can boot with nomodeset kernel parameter.

I added  'nomodeset' to the "linux" -line in Grub for kernel 6.2 and now the logout works. So this looks like it very likely is the firmware issue with Ubuntu Jammy.
Comment 9 Lassi Väätämöinen 2023-08-09 14:07:21 UTC
Reported in Ubuntu Launchpad: https://bugs.launchpad.net/ubuntu/+source/linux-firmware/+bug/2030882