Yesterday, after the update (KDE Neon plasma 5.20.3, I have the black screen after login into my main (usual) user. But

1) everything is regular in the other user

2) even in my user I can see the screen, after login, just for a second or two and then it goes black

3) even in my user you can see the single windows and I can call up practically any application from the terminal (alt + F2) and I can move from one window to another with alt + tab.

EDIT

I tried to change the privileges of other user, and so a) I got an error message in doing this , b) now the screen is black even for the other user.
So, I created a new user, with root privileges, and it works normally (normal desktop screen).

This is the log of .xsession-errors

Code: Select all

The X11 connection broke: I/O error (code 1)
XIO:  fatal IO error 22 (Invalid argument) on X server ":0"
      after 105552 requests (105552 known processed) with 0 events remaining.
QObject::~QObject: Timers cannot be stopped from another thread
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
bluedevil: Destroyed
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
QDBusAbstractAdaptor: Cannot relay signal KDEDModule::moduleDeleted(KDEDModule*): Pointers are not supported: KDEDModule*
The X11 connection broke: I/O error (code 1)
XIO:  fatal IO error 9 (Bad file descriptor) on X server ":0"
      after 24 requests (24 known processed) with 0 events remaining.
QtDBus: cannot relay signals from parent QObject(0x55d9f2d84d30 "") unless they are emitted in the object's thread QThread(0x55d9f2c986b0 ""). Current thread is QSGRenderThread(0x55d9f3df3b90 "").
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread
Application::crashHandler() called with signal 11; recent crashes: 1
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = kwin_x11 path = /usr/bin pid = 7692
KCrash: Arguments: /usr/bin/kwin_x11
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi
Warning: socket path is too long
Icon theme "Adwaita" not found.
Icon theme "Adwaita" not found.
Couldn't start kglobalaccel from org.kde.kglobalaccel.service: QDBusError("org.freedesktop.DBus.Error.Disconnected", "Not connected to D-Bus server")
OpenGL vendor string:                   VMware, Inc.
OpenGL renderer string:                 llvmpipe (LLVM 10.0.0, 256 bits)
OpenGL version string:                  3.1 Mesa 20.0.8
OpenGL shading language version string: 1.40
Driver:                                 LLVMpipe
GPU class:                              Unknown
OpenGL version:                         3.1
GLSL version:                           1.40
Mesa version:                           20.0.8
X server version:                       1.20.8
Linux kernel version:                   5.4
Requires strict binding:                yes
GLSL shaders:                           yes
Texture NPOT support:                   yes
Virtual Machine:                        no
qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 1435, resource id: 2097201, major code: 3 (GetWindowAttributes), minor code: 0
qt.qpa.xcb: QXcbConnection: XCB error: 9 (BadDrawable), sequence: 1436, resource id: 2097201, major code: 14 (GetGeometry), minor code: 0
qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 2669, resource id: 6291493, major code: 18 (ChangeProperty), minor code: 0
qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 2725, resource id: 8388613, major code: 18 (ChangeProperty), minor code: 0


same problem after the same update and the same error messages