Plasma 6 black screen and coursor

erg_samowzbudnik · Posted: Mon Sep 09, 2024 8:01 am Post subject: Plasma 6 black screen and coursor

I read the news, followed advice regarding upgrade and emerged plasma-meta 6.

Got black screen and coursor upon logging in.

Random info:
I use amdgpu, sddm although startx also results in the same behaviour.
Profile: 41 (default/linux/amd64/23.0/hardened (stable)
I in make.conf USE="X alsa elogind -webengine kf6compat qt6"

I do not see anything helpful in either /var/log/Xorg.0.log or sddm.log

Please advise. I'll wgetpaste any info necessary from my now headless desktop ..

Ralphred · l33t Joined: 31 Dec 2013 Posts: 653

rab0171610 · Guru Joined: 24 Dec 2022 Posts: 423

Make sure to create a new user account and log in as that user. If that user can log in but your user cannot, then it is a configuration issue. At that point you can clear the files in ~/.cache. If that doesn't fix it, then you can move the ~./config directory and start moving files back one or two at a time until you figure out which one is preventing you from logging in.
If the new user cannot log in, then you know it is not just a configuration issue (settings, themes, fonts, plasmoids, wallpapers, etc.).

Goverp · Advocate Joined: 07 Mar 2007 Posts: 2179

The terminal output from using startx might contain something useful, as well as a heck of a lot of garbage. It might help to redirect stdout to a file (a) for paging through, and (b) so that only stderr is left, which might have some useful error messages.

Sorry, suffering brain fade :-)

. Of course you need to send both stderr and stdout to a file or separate files, as a working KDE environment will hide any terminal output. Doh!
_________________
Greybeard

erg_samowzbudnik · Posted: Tue Sep 10, 2024 9:53 am Post subject:

Thanks for tips!

@Ralphred: nothing related as far as I can see

@rab171610: the same behaviour for a new user

@Goverp: This yields some data! I get stuff like:

Couldn't start kglobalaccel from org.kde.kglobalaccel.service: QDBusError("org.freedesktop.DBus.Error.ServiceUnknown", "The name org.kde.kglobalaccel was not provided by any .service files")
QDBusObjectPath: invalid path"/modules/kded_plasma-welcome"
kf.dbusaddons: The kded module name "kded_plasma-welcome " is invalid!
org.kde.plasma.printmanager.kded: unable to register service to dbus
org.kde.kameleon: found no RGB LED devices
QDBusObjectPath: invalid path "/modules/plasma-session-shortcuts"
kf.dbusaddons: The mded module name "plasma-session-shortcuts" is invalid!
org.kde.colorcorrectlocationupdater: Geolocator stopped
ksc_touchpad: Using X11 backend
(II) AIGLX: Suspending AIGLX clients for VT switch

wjb · Posted: Tue Sep 10, 2024 9:55 am Post subject:

The Plasma update changes your login to use Plasma Wayland; if you weren't already using Wayland try logging in with Plasma X11.

The update also patches a lot of .desktop files in /etc - make sure you've accepted these changes with dispatch-conf or etc-update.

erg_samowzbudnik · Posted: Tue Sep 10, 2024 9:56 am Post subject:

@Ralphred: Although now that I look closer at dmesg I do see:

plasmashell: segfault at 0 ip <blah blah>
Code: Unable to access opcode bytes at <blah blah

Also segfaulting:
- QQuckPixmapReal
- kwin_wayland
- xwaylandvideobr

erg_samowzbudnik · Posted: Tue Sep 10, 2024 9:59 am Post subject:

@wjb: should have mentioned: did try that a few times. Once I got Firefox window open, as I toggled Alt-tab to see any more open apps, it vanished (as in: I couldn't see it). No desktop taskbar visible, nothing worked. I can't replicate it anymore, it's just a black screen with coursor.

I did run etc-update after world update

mpiepgrass · n00b Joined: 10 Sep 2024 Posts: 1

I had a similar issue with a black screen and cursor after the Plasma 6 update, but in my case it would eventually start plasma after 2 or 3 minutes.
I found the issue had something to do a systemd service that I set up for the user. To fix it I needed to add:

sokhapkin · Posted: Wed Sep 11, 2024 3:33 pm Post subject:

https://bugs.kde.org/show_bug.cgi?id=492886

erg_samowzbudnik · Posted: Mon Sep 16, 2024 8:55 pm Post subject:

Temporary 'solution': move to xfce4 :roll:

asturm · Developer Joined: 05 Apr 2007 Posts: 9272

Post

emerge --info

*likely* fixed by building qtbase with -march=x86-64-v2 instead of what you have now.

erg_samowzbudnik · Posted: Wed Sep 18, 2024 11:56 am Post subject:

@asturm:

Thanks, that did it.
I guess I could mark this a 'solved', but is it?
I'm not following related threads closely but this looks like a major failure. Is this a gcc bug? A silicon bug? Something else?

I wonder should I make CXXFLAGS="-march=x86-64-v2" apply globally proactively or wait for randomly crashing applications and rebuild them only then?

I mean: how much should I worry?