A similar question was asked, but did not solve if startx is working: Sddm is not starting but in theory everything is working!
echo 'exec /usr/bin/startplasma-x11' > ~/.xinitrc worked to make startx start KDE on top of Ubuntu server. SDDM status is active, and used dpkg-reconfigure sddm however I still have blinking cursor on tty1 and tty7+. (This is inside KVM/virt-mgr, but shouldnt matter). startx starts Kubuntu DE, but still cant get to login screen by using logout. Am using sddm --example-config > /etc/sddm.conf for default config. I checked /var/log/Xorg.0.log and /var/log/sddm.log. I also tried with sddm & and then startx &.
[13:02:04.305] (II) DAEMON: Initializing...
[13:02:04.313] (II) DAEMON: Starting...
[13:02:04.313] (II) DAEMON: Logind interface found
[ 616.035]
X.Org X Server 1.20.13
X Protocol Version 11, Revision 0
[ 616.036] Build Operating System: linux Ubuntu
[ 616.036] Current Operating System: Linux ubuntu 5.4.0-100-generic #113-Ubuntu SMP Thu Feb 3 18:43:29 UTC 2022 x86_64
[ 616.036] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-5.4.0-100-generic root=UUID=5d51cbd2-a1de-48f6-b8b6-00709c787fa0 ro gfxpayload=1920x1080x32
[ 616.036] Build Date: 14 December 2021 02:14:13PM
[ 616.036] xorg-server 2:1.20.13-1ubuntu1~20.04.2 (For technical support please see http://www.ubuntu.com/support)
[ 616.036] Current version of pixman: 0.38.4
[ 616.036] Before reporting problems, check http://wiki.x.org
to make sure that you have the latest version.
[ 616.036] Markers: (--) probed, (**) from config file, (==) default setting,
(++) from command line, (!!) notice, (II) informational,
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[ 616.037] (==) Log file: "/var/log/Xorg.0.log", Time: Sat Feb 19 13:02:13 2022
[ 616.038] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[ 616.038] (==) No Layout section. Using the first Screen section.
[ 616.038] (==) No screen section available. Using defaults.
[ 616.038] (**) |-->Screen "Default Screen Section" (0)
[ 616.038] (**) | |-->Monitor "<default monitor>"
[ 616.038] (==) No monitor specified for screen "Default Screen Section".
Using a default monitor configuration.
[ 616.038] (==) Automatically adding devices
[ 616.038] (==) Automatically enabling devices
[ 616.038] (==) Automatically adding GPU devices
[ 616.038] (==) Automatically binding GPU devices
[ 616.038] (==) Max clients allowed: 256, resource mask: 0x1fffff
[ 616.038] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist.
[ 616.038] Entry deleted from font path.
[ 616.038] (WW) The directory "/usr/share/fonts/X11/100dpi/" does not exist.
[ 616.038] Entry deleted from font path.
[ 616.038] (WW) The directory "/usr/share/fonts/X11/75dpi/" does not exist.
[ 616.038] Entry deleted from font path.
[ 616.038] (WW) The directory "/usr/share/fonts/X11/100dpi" does not exist.
[ 616.038] Entry deleted from font path.
[ 616.038] (WW) The directory "/usr/share/fonts/X11/75dpi" does not exist.
[ 616.038] Entry deleted from font path.
[ 616.038] (==) FontPath set to:
/usr/share/fonts/X11/misc,
/usr/share/fonts/X11/Type1,
built-ins
[ 616.038] (==) ModulePath set to "/usr/lib/xorg/modules"
[ 616.038] (II) The server relies on udev to provide the list of input devices.
If no devices become available, reconfigure udev or disable AutoAddDevices.
[ 616.038] (II) Loader magic: 0x55eb5ab29020
[ 616.038] (II) Module ABI versions:
[ 616.038] X.Org ANSI C Emulation: 0.4
[ 616.038] X.Org Video Driver: 24.1
[ 616.038] X.Org XInput driver : 24.1
[ 616.038] X.Org Server Extension : 10.0
[ 616.040] (--) using VT number 2
[ 616.040] (II) systemd-logind: logind integration requires -keeptty and -keeptty was not provided, disabling logind integration
[ 616.044] (--) PCI:*(0@0:1:0) 1af4:1050:1af4:1100 rev 1, Mem @ 0xfc000000/8388608, 0xfd800000/16384, 0xfea14000/4096, BIOS @ 0x????????/131072
[ 616.044] (II) LoadModule: "glx"
[ 616.045] (II) Loading /usr/lib/xorg/modules/extensions/libglx.so
[ 616.046] (II) Module glx: vendor="X.Org Foundation"
[ 616.046] compiled for 1.20.13, module version = 1.0.0
[ 616.046] ABI class: X.Org Server Extension, version 10.0
[ 616.047] (==) Matched modesetting as autoconfigured driver 0
[ 616.047] (==) Matched fbdev as autoconfigured driver 1
[ 616.047] (==) Matched vesa as autoconfigured driver 2
[ 616.047] (==) Assigned the driver to the xf86ConfigLayout
[ 616.047] (II) LoadModule: "modesetting"
[ 616.047] (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so
[ 616.047] (II) Module modesetting: vendor="X.Org Foundation"
[ 616.047] compiled for 1.20.13, module version = 1.20.13
[ 616.047] Module class: X.Org Video Driver
[ 616.047] ABI class: X.Org Video Driver, version 24.1
[ 616.047] (II) LoadModule: "fbdev"
[ 616.047] (II) Loading /usr/lib/xorg/modules/drivers/fbdev_drv.so
[ 616.047] (II) Module fbdev: vendor="X.Org Foundation"
[ 616.047] compiled for 1.20.1, module version = 0.5.0
[ 616.047] Module class: X.Org Video Driver
[ 616.047] ABI class: X.Org Video Driver, version 24.0
[ 616.047] (II) LoadModule: "vesa"
[ 616.047] (II) Loading /usr/lib/xorg/modules/drivers/vesa_drv.so
[ 616.047] (II) Module vesa: vendor="X.Org Foundation"
[ 616.047] compiled for 1.20.4, module version = 2.4.0
[ 616.047] Module class: X.Org Video Driver
[ 616.047] ABI class: X.Org Video Driver, version 24.0
[ 616.047] (II) modesetting: Driver for Modesetting Kernel Drivers: kms
[ 616.047] (II) FBDEV: driver for framebuffer: fbdev
[ 616.047] (II) VESA: driver for VESA chipsets: vesa
[ 616.049] (EE) open /dev/dri/card0: No such file or directory
[ 616.049] (WW) Falling back to old probe method for modesetting
[ 616.049] (EE) open /dev/dri/card0: No such file or directory
[ 616.049] (II) Loading sub module "fbdevhw"
[ 616.049] (II) LoadModule: "fbdevhw"
[ 616.049] (II) Loading /usr/lib/xorg/modules/libfbdevhw.so
[ 616.049] (II) Module fbdevhw: vendor="X.Org Foundation"
[ 616.049] compiled for 1.20.13, module version = 0.0.2
[ 616.049] ABI class: X.Org Video Driver, version 24.1
[ 616.049] (**) FBDEV(1): claimed PCI slot 0@0:1:0
[ 616.049] (II) FBDEV(1): using default device
[ 616.049] (EE) Screen 0 deleted because of no matching config section.
[ 616.049] (II) UnloadModule: "modesetting"
[ 616.049] (II) FBDEV(0): Creating default Display subsection in Screen section
"Default Screen Section" for depth/fbbpp 24/32
[ 616.049] (==) FBDEV(0): Depth 24, (==) framebuffer bpp 32
[ 616.049] (==) FBDEV(0): RGB weight 888
[ 616.049] (==) FBDEV(0): Default visual is TrueColor
[ 616.049] (==) FBDEV(0): Using gamma correction (1.0, 1.0, 1.0)
[ 616.049] (II) FBDEV(0): hardware: VESA VGA (video memory: 1216kB)
[ 616.049] (II) FBDEV(0): checking modes against framebuffer device...
[ 616.049] (II) FBDEV(0): checking modes against monitor...
[ 616.049] (II) FBDEV(0): Virtual size is 640x480 (pitch 640)
[ 616.049] (**) FBDEV(0): Built-in mode "current": 30.7 MHz, 36.9 kHz, 73.3 Hz
[ 616.049] (II) FBDEV(0): Modeline "current"x0.0 30.72 640 672 752 832 480 484 488 504 -hsync -vsync -csync (36.9 kHz b)
[ 616.049] (==) FBDEV(0): DPI set to (96, 96)
[ 616.049] (II) Loading sub module "fb"
[ 616.049] (II) LoadModule: "fb"
[ 616.049] (II) Loading /usr/lib/xorg/modules/libfb.so
[ 616.050] (II) Module fb: vendor="X.Org Foundation"
[ 616.050] compiled for 1.20.13, module version = 1.0.0
[ 616.050] ABI class: X.Org ANSI C Emulation, version 0.4
[ 616.050] (**) FBDEV(0): using shadow framebuffer
[ 616.050] (II) Loading sub module "shadow"
[ 616.050] (II) LoadModule: "shadow"
[ 616.050] (II) Loading /usr/lib/xorg/modules/libshadow.so
[ 616.050] (II) Module shadow: vendor="X.Org Foundation"
[ 616.050] compiled for 1.20.13, module version = 1.1.0
[ 616.050] ABI class: X.Org ANSI C Emulation, version 0.4
[ 616.050] (II) UnloadModule: "vesa"
[ 616.050] (II) Unloading vesa
[ 616.050] (II) FBDEV(0): FBIOBLANK: Invalid argument (Screen blanking not supported by kernel - disabling)
[ 616.050] (==) FBDEV(0): Backing store enabled
[ 616.050] (==) FBDEV(0): DPMS enabled
[ 616.051] (II) Initializing extension Generic Event Extension
[ 616.051] (II) Initializing extension SHAPE
[ 616.051] (II) Initializing extension MIT-SHM
[ 616.051] (II) Initializing extension XInputExtension
[ 616.051] (II) Initializing extension XTEST
[ 616.051] (II) Initializing extension BIG-REQUESTS
[ 616.051] (II) Initializing extension SYNC
[ 616.051] (II) Initializing extension XKEYBOARD
[ 616.051] (II) Initializing extension XC-MISC
[ 616.052] (II) Initializing extension SECURITY
[ 616.052] (II) Initializing extension XFIXES
[ 616.052] (II) Initializing extension RENDER
[ 616.052] (II) Initializing extension RANDR
[ 616.053] (II) Initializing extension COMPOSITE
[ 616.053] (II) Initializing extension DAMAGE
[ 616.053] (II) Initializing extension MIT-SCREEN-SAVER
[ 616.053] (II) Initializing extension DOUBLE-BUFFER
[ 616.053] (II) Initializing extension RECORD
[ 616.053] (II) Initializing extension DPMS
[ 616.054] (II) Initializing extension Present
[ 616.054] (II) Initializing extension DRI3
[ 616.054] (II) Initializing extension X-Resource
[ 616.054] (II) Initializing extension XVideo
[ 616.054] (II) Initializing extension XVideo-MotionCompensation
[ 616.054] (II) Initializing extension SELinux
[ 616.054] (II) SELinux: Disabled on system
[ 616.054] (II) Initializing extension GLX
[ 616.054] (II) AIGLX: Screen 0 is not DRI2 capable
[ 616.088] (II) IGLX: Loaded and initialized swrast
[ 616.088] (II) GLX: Initialized DRISWRAST GL provider for screen 0
[ 616.088] (II) Initializing extension XFree86-VidModeExtension
[ 616.088] (II) Initializing extension XFree86-DGA
[ 616.088] (II) Initializing extension XFree86-DRI
[ 616.088] (II) Initializing extension DRI2
[ 616.124] (II) config/udev: Adding input device Power Button (/dev/input/event0)
[ 616.124] (**) Power Button: Applying InputClass "libinput keyboard catchall"
[ 616.124] (II) LoadModule: "libinput"
[ 616.124] (II) Loading /usr/lib/xorg/modules/input/libinput_drv.so
[ 616.126] (II) Module libinput: vendor="X.Org Foundation"
[ 616.126] compiled for 1.20.4, module version = 0.29.0
[ 616.126] Module class: X.Org XInput Driver
[ 616.126] ABI class: X.Org XInput driver, version 24.1
[ 616.126] (II) Using input driver 'libinput' for 'Power Button'
[ 616.126] (**) Power Button: always reports core events
[ 616.126] (**) Option "Device" "/dev/input/event0"
[ 616.126] (**) Option "_source" "server/udev"
[ 616.128] (II) event0 - Power Button: is tagged by udev as: Keyboard
[ 616.128] (II) event0 - Power Button: device is a keyboard
[ 616.128] (II) event0 - Power Button: device removed
[ 616.145] (**) Option "config_info" "udev:/sys/devices/LNXSYSTM:00/LNXPWRBN:00/input/input0/event0"
[ 616.145] (II) XINPUT: Adding extended input device "Power Button" (type: KEYBOARD, id 6)
[ 616.145] (**) Option "xkb_model" "pc105"
[ 616.145] (**) Option "xkb_layout" "us"
[ 616.146] (II) event0 - Power Button: is tagged by udev as: Keyboard
[ 616.146] (II) event0 - Power Button: device is a keyboard
[ 616.146] (II) config/udev: Adding input device QEMU QEMU USB Tablet (/dev/input/event2)
[ 616.146] (**) QEMU QEMU USB Tablet: Applying InputClass "libinput pointer catchall"
[ 616.146] (II) Using input driver 'libinput' for 'QEMU QEMU USB Tablet'
[ 616.146] (**) QEMU QEMU USB Tablet: always reports core events
[ 616.146] (**) Option "Device" "/dev/input/event2"
[ 616.146] (**) Option "_source" "server/udev"
[ 616.206] (II) event2 - QEMU QEMU USB Tablet: is tagged by udev as: Mouse
[ 616.206] (II) event2 - QEMU QEMU USB Tablet: device is a pointer
[ 616.206] (II) event2 - QEMU QEMU USB Tablet: device removed
[ 616.237] (**) Option "config_info" "udev:/sys/devices/pci0000:00/0000:00:1d.7/usb1/1-1/1-1:1.0/0003:0627:0001.0001/input/input4/event2"
[ 616.237] (II) XINPUT: Adding extended input device "QEMU QEMU USB Tablet" (type: MOUSE, id 7)
[ 616.237] (**) Option "AccelerationScheme" "none"
[ 616.237] (**) QEMU QEMU USB Tablet: (accel) selected scheme none/0
[ 616.237] (**) QEMU QEMU USB Tablet: (accel) acceleration factor: 2.000
[ 616.237] (**) QEMU QEMU USB Tablet: (accel) acceleration threshold: 4
[ 616.298] (II) event2 - QEMU QEMU USB Tablet: is tagged by udev as: Mouse
[ 616.298] (II) event2 - QEMU QEMU USB Tablet: device is a pointer
[ 616.299] (II) config/udev: Adding input device QEMU QEMU USB Tablet (/dev/input/mouse0)
[ 616.299] (II) No input driver specified, ignoring this device.
[ 616.299] (II) This device may have been added with another device file.
[ 616.299] (II) config/udev: Adding input device AT Translated Set 2 keyboard (/dev/input/event1)
[ 616.299] (**) AT Translated Set 2 keyboard: Applying InputClass "libinput keyboard catchall"
[ 616.299] (II) Using input driver 'libinput' for 'AT Translated Set 2 keyboard'
[ 616.299] (**) AT Translated Set 2 keyboard: always reports core events
[ 616.299] (**) Option "Device" "/dev/input/event1"
[ 616.299] (**) Option "_source" "server/udev"
[ 616.300] (II) event1 - AT Translated Set 2 keyboard: is tagged by udev as: Keyboard
[ 616.300] (II) event1 - AT Translated Set 2 keyboard: device is a keyboard
[ 616.301] (II) event1 - AT Translated Set 2 keyboard: device removed
[ 616.321] (**) Option "config_info" "udev:/sys/devices/platform/i8042/serio0/input/input1/event1"
[ 616.321] (II) XINPUT: Adding extended input device "AT Translated Set 2 keyboard" (type: KEYBOARD, id 8)
[ 616.321] (**) Option "xkb_model" "pc105"
[ 616.321] (**) Option "xkb_layout" "us"
[ 616.322] (II) event1 - AT Translated Set 2 keyboard: is tagged by udev as: Keyboard
[ 616.322] (II) event1 - AT Translated Set 2 keyboard: device is a keyboard
[ 616.323] (II) config/udev: Adding input device ImExPS/2 Generic Explorer Mouse (/dev/input/event3)
[ 616.323] (**) ImExPS/2 Generic Explorer Mouse: Applying InputClass "libinput pointer catchall"
[ 616.323] (II) Using input driver 'libinput' for 'ImExPS/2 Generic Explorer Mouse'
[ 616.323] (**) ImExPS/2 Generic Explorer Mouse: always reports core events
[ 616.323] (**) Option "Device" "/dev/input/event3"
[ 616.323] (**) Option "_source" "server/udev"
[ 616.324] (II) event3 - ImExPS/2 Generic Explorer Mouse: is tagged by udev as: Mouse
[ 616.324] (II) event3 - ImExPS/2 Generic Explorer Mouse: device is a pointer
[ 616.324] (II) event3 - ImExPS/2 Generic Explorer Mouse: device removed
[ 616.353] (**) Option "config_info" "udev:/sys/devices/platform/i8042/serio1/input/input3/event3"
[ 616.353] (II) XINPUT: Adding extended input device "ImExPS/2 Generic Explorer Mouse" (type: MOUSE, id 9)
[ 616.353] (**) Option "AccelerationScheme" "none"
[ 616.353] (**) ImExPS/2 Generic Explorer Mouse: (accel) selected scheme none/0
[ 616.353] (**) ImExPS/2 Generic Explorer Mouse: (accel) acceleration factor: 2.000
[ 616.353] (**) ImExPS/2 Generic Explorer Mouse: (accel) acceleration threshold: 4
[ 616.354] (II) event3 - ImExPS/2 Generic Explorer Mouse: is tagged by udev as: Mouse
[ 616.354] (II) event3 - ImExPS/2 Generic Explorer Mouse: device is a pointer
[ 616.354] (II) config/udev: Adding input device ImExPS/2 Generic Explorer Mouse (/dev/input/mouse1)
[ 616.354] (II) No input driver specified, ignoring this device.
[ 616.355] (II) This device may have been added with another device file.
[ 636.736] (II) event0 - Power Button: device removed
[ 636.753] (II) event2 - QEMU QEMU USB Tablet: device removed
[ 636.785] (II) event1 - AT Translated Set 2 keyboard: device removed
[ 636.801] (II) event3 - ImExPS/2 Generic Explorer Mouse: device removed
[ 636.834] (II) UnloadModule: "libinput"
[ 636.834] (II) UnloadModule: "libinput"
[ 636.834] (II) UnloadModule: "libinput"
[ 636.834] (II) UnloadModule: "libinput"
[ 636.838] (II) Server terminated successfully (0). Closing log file.
