Problems begin as from sddm cannot to start :)

karma: -1

Works great! LGTM! =)

python-qt5-5.7-3.fc25 is not submitted at the moment so I'm not sure whether this is the reason

kdm can start but after that nothing starts too

Had to downgrade :)

works for me

Jan 28 10:08:11 systemd[1]: sddm.service: Start request repeated too quickly.

Jan 28 10:08:11 systemd[1]: Failed to start Simple Desktop Display Manager.

Jan 28 10:08:11 systemd[1]: sddm.service: Unit entered failed state.

Jan 28 10:08:11 systemd[1]: sddm.service: Failed with result 'start-limit-hit'.

-- Reboot --

Jan 28 10:25:24 systemd[1]: sddm.service: Failed to send unit remove signal for sddm.service: Transport endpoint is not connected

-- Reboot --

Jan 28 10:29:26 systemd[1]: Started Simple Desktop Display Manager.

-- Reboot --

Jan 28 11:03:30 systemd[1]: sddm.service: Failed to send unit remove signal for sddm.service: Transport endpoint is not connected

-- Reboot --

Jan 28 11:10:39 systemd[1]: sddm.service: Collecting.

-- Reboot --

Jan 28 11:33:12 systemd[1]: Started Simple Desktop Display Manager.

Jan 28 11:33:36 sddm[952]: Oops, secure memory pool already initialized

for the sddm failures, if anyone seeing that can get an abrt report and/or backtrace, please file a bug. thanks.

You have taken all wrong. It's all not about sddm :)

sddm is the thing failing to start, potentially crashing. We need to know more about how and why that is happening.

And someone, of course, could add to stable threshold for seeing reports with far-reaching effects ;)

I don't know for sure. Maybe, this can help:

sddm: QProcess: Destroyed while process ("/usr/libexec/sddm-helper") is still running.

We can bypass sddm with something else, that starts, and see how KDE desktop environment does not start too :)

So the only way out is downgrading. Updating to python-qt5-5.7-3.fc25 does not help :)

Hypothetic this may show only with NVIDIA-Linux-x86_64-378.09 or else driver usage

Some behindhand journal logs on the off chance :))

Jan 28 10:04:44  sddm-greeter[982]: QObject: Cannot create
children for a parent that is in a different thread.

       (Parent is SDDM::GreeterApp(0x7f.......f0), 
       parent's thread is QThread(0x56........50), 
       current thread is QThread(0x56........d0)

"There are still \"-1\" items in the process of being created at engine destruction."

Some log messages just after update & before blank screen:

Jan 29 22:43:14  kdeinit5[1311]: QObject::connect: invalid null parameter

Jan 29 22:53:13  kwin_x11[1357]: QPainter::begin: Paint device returned engine == 0, type: 3

 Jan 29 22:53:18  kwin_x11[1357]: QXcbConnection: XCB error: 3 (BadWindow), sequence: 9245, resource id: 38049708, major code: 3 (GetWindowAttributes), minor code: 0

Jan 29 22:53:18  kwin_x11[1357]: QXcbConnection: XCB error: 9 (BadDrawable), sequence: 9246, resource id: 38049708, major code: 14 (GetGeometry), minor code: 0

Jan 29 22:53:18  plasmashell[1373]: QXcbConnection: XCB error: 2 (BadValue), sequence: 44547, resource id: 58720304, major code: 141 (Unknown), minor code: 3

Jan 29 22:53:20  kwin_x11[1357]: QXcbWindow: Unhandled client message: "_NET_CURRENT_DESKTOP"

Jan 29 22:57:52  plasmashell[1373]: ShaderEffect: Property 'source' is not assigned a valid texture provider (void*).

Jan 29 22:57:52  plasmashell[1373]: ShaderEffect: Property 'maskSource' is not assigned a valid texture provider (void*).

Jan 29 23:01:51  plasmashell[1373]: QDBusObjectPath: invalid path ""

Jan 29 23:02:27  kwin_x11[1357]: QThread: Destroyed while thread is still running

Jan 29 23:02:32  kdeinit5[1311]: QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*

Jan 29 23:14:43  klauncher[1338]: Connecting to deprecated signal QDBusConnectionInterface::serviceOwnerChanged(QString,QString,QString)

Bound to acknowledge, that with all available at the moment test updates everything finally turned out!

It stands to mention that sddm.conf was saved as .rpmnew with 'EnableHiDPI=false' commented out ...but this stunning mind-blowing blue-screen-of-death-styled welcome screen now seems worth the salt! 😹

So on my part no longer see some reasons to temporize this update 😌

Works for me.

After installing the latest SDDM update (sddm-0.14.0-7.fc25.x86_64) sddm does not crash and I can login OK.

Works fine on x86_64.

LGTM

Works

Works fine for me.

wfm

works for me