Debian 12 boot fails to load lightdm and stops

Debian 12 fails to boot after last upgrades writing sth like

[failed] Lightm did not load

The content of /var/log/lightdm/lightdm.log is as follows

[+0.00s] DEBUG: Starting Light Display Manager 1.26.0, UID=0 PID=722 [+0.00s] DEBUG: Loading configuration dirs from /usr/share/lightdm/lightdm.conf.d [+0.00s] DEBUG: Loading configuration from /usr/share/lightdm/lightdm.conf.d/01_debian.conf [+0.00s] DEBUG: Loading configuration dirs from /usr/local/share/lightdm/lightdm.conf.d [+0.00s] DEBUG: Loading configuration dirs from /etc/xdg/lightdm/lightdm.conf.d [+0.00s] DEBUG: Loading configuration from /etc/lightdm/lightdm.conf [+0.00s] DEBUG: Registered seat module local [+0.00s] DEBUG: Registered seat module xremote [+0.00s] DEBUG: Registered seat module unity [+0.00s] DEBUG: Using D-Bus name org.freedesktop.DisplayManager [+0.00s] DEBUG: Using cross-namespace EXTERNAL authentication (this will deadlock if server is GDBus < 2.73.3) [+0.00s] DEBUG: _g_io_module_get_default: Found default implementation local (GLocalVfs) for ‘gio-vfs’ [+0.01s] DEBUG: Monitoring logind for seats [+0.01s] DEBUG: New seat added from logind: seat0 [+0.01s] DEBUG: Seat seat0: Loading properties from config section Seat:* [+0.01s] DEBUG: Seat seat0 has property CanMultiSession=no [+0.01s] DEBUG: Seat seat0: Starting [+0.01s] DEBUG: Seat seat0: Creating greeter session [+0.01s] DEBUG: Seat seat0: Creating display server of type x [+0.01s] DEBUG: Using VT 7 [+0.01s] DEBUG: Seat seat0: Starting local X display on VT 7 [+0.01s] DEBUG: XServer 0: Logging to /var/log/lightdm/x-0.log [+0.01s] DEBUG: XServer 0: Writing X server authority to /var/run/lightdm/root/:0 [+0.01s] DEBUG: XServer 0: Launching X Server [+0.01s] DEBUG: Launching process 728: /usr/bin/X :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch [+0.01s] DEBUG: XServer 0: Waiting for ready signal from X server :0 [+0.01s] DEBUG: Acquired bus name org.freedesktop.DisplayManager [+0.01s] DEBUG: Registering seat with bus path /org/freedesktop/DisplayManager/Seat0 [+0.01s] DEBUG: Loading users from org.freedesktop.Accounts [+0.01s] DEBUG: User /org/freedesktop/Accounts/User1000 added [+0.31s] DEBUG: Process 728 exited with return value 1 [+0.31s] DEBUG: XServer 0: X server stopped [+0.31s] DEBUG: Releasing VT 7 [+0.31s] DEBUG: XServer 0: Removing X server authority /var/run/lightdm/root/:0 [+0.31s] DEBUG: Seat seat0: Display server stopped [+0.31s] DEBUG: Seat seat0: Stopping session [+0.31s] DEBUG: Seat seat0: Session stopped [+0.31s] DEBUG: Seat seat0: Stopping display server, no sessions require it [+0.31s] DEBUG: Seat seat0: Stopping; greeter display server failed to start [+0.31s] DEBUG: Seat seat0: Stopping [+0.31s] DEBUG: Seat seat0: Stopped [+0.31s] DEBUG: Required seat has stopped [+0.31s] DEBUG: Stopping display manager [+0.31s] DEBUG: Display manager stopped [+0.31s] DEBUG: Stopping daemon [+0.31s] DEBUG: Exiting with return value 1 

sudo Xorg -configure gives

 X.Org X Server 1.21.1.7 X Protocol Version 11, Revision 0 Current Operating System: Linux ariel-ThinkPad-Edge 6.1.0-20-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.85-1 (2024-04-11) x86_64 Kernel command line: BOOT_IMAGE=/boot/vmlinuz-6.1.0-20-amd64 root=UUID=2d57e90e-866c-490a-9449-22621e9f01c2 ro init_on_alloc=0 quiet xorg-server 2:21.1.7-3+deb12u7 (https://www.debian.org/support) Current version of pixman: 0.42.2 Before reporting problems, check http://wiki.x.org to make sure that you have the latest version. Markers: (--) probed, (**) from config file, (==) default setting, (++) from command line, (!!) notice, (II) informational, (WW) warning, (EE) error, (NI) not implemented, (??) unknown. (==) Log file: "/var/log/Xorg.0.log", Time: Mon Apr 29 11:36:45 2024 List of video drivers: amdgpu ati intel nouveau qxl radeon vmware modesetting fbdev vesa (++) Using config file: "/root/xorg.conf.new" (==) Using system config directory "/usr/share/X11/xorg.conf.d" Number of created screens does not match number of detected devices. Configuration failed. (EE) Server terminated with error (2). Closing log file. 

Reinstalling lightdm, xfce4, turning to gnome or mate doesn't help. Can it be solved without total reinstallation ?

Xorg.0.log is as follows

[ 1310.508] X.Org X Server 1.21.1.7 X Protocol Version 11, Revision 0 [ 1310.508] Current Operating System: Linux ariel-ThinkPad-Edge 6.1.0-20-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.85-1 (2024-04-11) x86_64 [ 1310.508] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-6.1.0-20-amd64 root=UUID=2d57e90e-866c-490a-9449-22621e9f01c2 ro init_on_alloc=0 quiet [ 1310.508] xorg-server 2:21.1.7-3+deb12u7 (https://www.debian.org/support) [ 1310.508] Current version of pixman: 0.42.2 [ 1310.508] Before reporting problems, check http://wiki.x.org to make sure that you have the latest version. [ 1310.508] Markers: (--) probed, (**) from config file, (==) default setting, (++) from command line, (!!) notice, (II) informational, (WW) warning, (EE) error, (NI) not implemented, (??) unknown. [ 1310.509] (==) Log file: "/var/log/Xorg.0.log", Time: Mon Apr 29 11:36:45 2024 [ 1310.509] (II) Loader magic: 0x56321c153f00 [ 1310.509] (II) Module ABI versions: [ 1310.509] X.Org ANSI C Emulation: 0.4 [ 1310.509] X.Org Video Driver: 25.2 [ 1310.509] X.Org XInput driver : 24.4 [ 1310.509] X.Org Server Extension : 10.0 [ 1310.510] (--) using VT number 2 [ 1310.510] (II) systemd-logind: logind integration requires -keeptty and -keeptty was not provided, disabling logind integration [ 1310.514] (--) PCI:*(1@0:0:0) 10de:0a34:17aa:38cd rev 162, Mem @ 0xd2000000/16777216, 0xc0000000/268435456, 0xd0000000/33554432, I/O @ 0x00006000/128, BIOS @ 0x????????/131072 [ 1310.515] List of video drivers: [ 1310.515] amdgpu [ 1310.515] ati [ 1310.515] intel [ 1310.515] nouveau [ 1310.515] qxl [ 1310.515] radeon [ 1310.515] vmware [ 1310.515] modesetting [ 1310.515] fbdev [ 1310.515] vesa [ 1310.515] (II) LoadModule: "amdgpu" [ 1310.515] (II) Loading /usr/lib/xorg/modules/drivers/amdgpu_drv.so [ 1310.516] (II) Module amdgpu: vendor="X.Org Foundation" [ 1310.516] compiled for 1.21.1.7, module version = 23.0.0 [ 1310.516] Module class: X.Org Video Driver [ 1310.516] ABI class: X.Org Video Driver, version 25.2 [ 1310.516] (II) LoadModule: "ati" [ 1310.516] (II) Loading /usr/lib/xorg/modules/drivers/ati_drv.so [ 1310.516] (II) Module ati: vendor="X.Org Foundation" [ 1310.516] compiled for 1.21.1.3, module version = 19.1.0 [ 1310.516] Module class: X.Org Video Driver [ 1310.516] ABI class: X.Org Video Driver, version 25.2 [ 1310.516] (II) LoadModule: "intel" [ 1310.516] (II) Loading /usr/lib/xorg/modules/drivers/intel_drv.so [ 1310.517] (II) Module intel: vendor="X.Org Foundation" [ 1310.517] compiled for 1.21.1.3, module version = 2.99.917 [ 1310.517] Module class: X.Org Video Driver [ 1310.517] ABI class: X.Org Video Driver, version 25.2 [ 1310.517] (II) LoadModule: "nouveau" [ 1310.517] (II) Loading /usr/lib/xorg/modules/drivers/nouveau_drv.so [ 1310.517] (II) Module nouveau: vendor="X.Org Foundation" [ 1310.517] compiled for 1.21.1.3, module version = 1.0.17 [ 1310.517] Module class: X.Org Video Driver [ 1310.517] ABI class: X.Org Video Driver, version 25.2 [ 1310.517] (II) LoadModule: "qxl" [ 1310.517] (II) Loading /usr/lib/xorg/modules/drivers/qxl_drv.so [ 1310.517] (II) Module qxl: vendor="X.Org Foundation" [ 1310.517] compiled for 1.21.1.3, module version = 0.1.5 [ 1310.517] Module class: X.Org Video Driver [ 1310.518] ABI class: X.Org Video Driver, version 25.2 [ 1310.518] (II) LoadModule: "radeon" [ 1310.518] (II) Loading /usr/lib/xorg/modules/drivers/radeon_drv.so [ 1310.518] (II) Module radeon: vendor="X.Org Foundation" [ 1310.518] compiled for 1.21.1.3, module version = 19.1.0 [ 1310.518] Module class: X.Org Video Driver [ 1310.518] ABI class: X.Org Video Driver, version 25.2 [ 1310.518] (II) LoadModule: "vmware" [ 1310.518] (II) Loading /usr/lib/xorg/modules/drivers/vmware_drv.so [ 1310.547] (II) Module vmware: vendor="X.Org Foundation" [ 1310.547] compiled for 1.21.1.7, module version = 13.3.0 [ 1310.547] Module class: X.Org Video Driver [ 1310.547] ABI class: X.Org Video Driver, version 25.2 [ 1310.547] (II) LoadModule: "modesetting" [ 1310.548] (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so [ 1310.548] (II) Module modesetting: vendor="X.Org Foundation" [ 1310.548] compiled for 1.21.1.7, module version = 1.21.1 [ 1310.548] Module class: X.Org Video Driver [ 1310.548] ABI class: X.Org Video Driver, version 25.2 [ 1310.548] (II) LoadModule: "fbdev" [ 1310.548] (II) Loading /usr/lib/xorg/modules/drivers/fbdev_drv.so [ 1310.548] (II) Module fbdev: vendor="X.Org Foundation" [ 1310.548] compiled for 1.21.1.3, module version = 0.5.0 [ 1310.548] Module class: X.Org Video Driver [ 1310.548] ABI class: X.Org Video Driver, version 25.2 [ 1310.548] (II) LoadModule: "vesa" [ 1310.548] (II) Loading /usr/lib/xorg/modules/drivers/vesa_drv.so [ 1310.549] (II) Module vesa: vendor="X.Org Foundation" [ 1310.549] compiled for 1.21.1.3, module version = 2.5.0 [ 1310.549] Module class: X.Org Video Driver [ 1310.549] ABI class: X.Org Video Driver, version 25.2 [ 1310.549] (II) NOUVEAU driver Date: Sat Jan 23 12:24:42 2021 -0500 [ 1310.549] (II) NOUVEAU driver for NVIDIA chipset families : [ 1310.549] RIVA TNT (NV04) [ 1310.549] RIVA TNT2 (NV05) [ 1310.549] GeForce 256 (NV10) [ 1310.549] GeForce 2 (NV11, NV15) [ 1310.549] GeForce 4MX (NV17, NV18) [ 1310.549] GeForce 3 (NV20) [ 1310.549] GeForce 4Ti (NV25, NV28) [ 1310.549] GeForce FX (NV3x) [ 1310.549] GeForce 6 (NV4x) [ 1310.549] GeForce 7 (G7x) [ 1310.549] GeForce 8 (G8x) [ 1310.549] GeForce 9 (G9x) [ 1310.549] GeForce GTX 2xx/3xx (GT2xx) [ 1310.549] GeForce GTX 4xx/5xx (GFxxx) [ 1310.550] GeForce GTX 6xx/7xx (GKxxx) [ 1310.550] GeForce GTX 9xx (GMxxx) [ 1310.550] GeForce GTX 10xx (GPxxx) [ 1310.550] (II) modesetting: Driver for Modesetting Kernel Drivers: kms [ 1310.550] (II) FBDEV: driver for framebuffer: fbdev [ 1310.550] (II) VESA: driver for VESA chipsets: vesa [ 1310.592] (++) Using config file: "/root/xorg.conf.new" [ 1310.592] (==) Using system config directory "/usr/share/X11/xorg.conf.d" [ 1310.592] (==) ServerLayout "X.org Configured" [ 1310.592] (**) |-->Screen "Screen0" (0) [ 1310.592] (**) | |-->Monitor "Monitor0" [ 1310.593] (**) | |-->Device "Card0" [ 1310.593] (**) |-->Input Device "Mouse0" [ 1310.593] (**) |-->Input Device "Keyboard0" [ 1310.593] (==) Automatically adding devices [ 1310.593] (==) Automatically enabling devices [ 1310.593] (==) Automatically adding GPU devices [ 1310.593] (==) Automatically binding GPU devices [ 1310.593] (==) Max clients allowed: 256, resource mask: 0x1fffff [ 1310.593] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist. [ 1310.593] Entry deleted from font path. [ 1310.593] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist. [ 1310.593] Entry deleted from font path. [ 1310.593] (**) FontPath set to: /usr/share/fonts/X11/misc, /usr/share/fonts/X11/100dpi/:unscaled, /usr/share/fonts/X11/75dpi/:unscaled, /usr/share/fonts/X11/Type1, /usr/share/fonts/X11/100dpi, /usr/share/fonts/X11/75dpi, built-ins, /usr/share/fonts/X11/misc, /usr/share/fonts/X11/100dpi/:unscaled, /usr/share/fonts/X11/75dpi/:unscaled, /usr/share/fonts/X11/Type1, /usr/share/fonts/X11/100dpi, /usr/share/fonts/X11/75dpi, built-ins [ 1310.593] (**) ModulePath set to "/usr/lib/xorg/modules" [ 1310.593] (WW) Hotplugging is on, devices using drivers 'kbd', 'mouse' or 'vmmouse' will be disabled. [ 1310.593] (WW) Disabling Mouse0 [ 1310.593] (WW) Disabling Keyboard0 [ 1310.729] (EE) [drm] Failed to open DRM device for pci:0000:01:00.0: -19 [ 1310.730] Number of created screens does not match number of detected devices. Configuration failed. [ 1310.730] (EE) Server terminated with error (2). Closing log file. 

I used to try to install cuda some time before the last upgrade. It led to gui malfunctioning , so i uninstalled cuda, returned to nouveau, and ran Xorg -configure and everything seemed to work. And it still works if i boot to the previous version of Debian on grub (sth like 6.8 instead of 6.10). Current xorg.conf is as follows

Section "ServerLayout" Identifier "X.org Configured" Screen 0 "Screen0" 0 0 InputDevice "Mouse0" "CorePointer" InputDevice "Keyboard0" "CoreKeyboard" EndSection Section "Files" ModulePath "/usr/lib/xorg/modules" FontPath "/usr/share/fonts/X11/misc" FontPath "/usr/share/fonts/X11/cyrillic" FontPath "/usr/share/fonts/X11/100dpi/:unscaled" FontPath "/usr/share/fonts/X11/75dpi/:unscaled" FontPath "/usr/share/fonts/X11/Type1" FontPath "/usr/share/fonts/X11/100dpi" FontPath "/usr/share/fonts/X11/75dpi" FontPath "built-ins" EndSection Section "Module" Load "glx" EndSection Section "InputDevice" Identifier "Keyboard0" Driver "kbd" EndSection Section "InputDevice" Identifier "Mouse0" Driver "mouse" Option "Protocol" "auto" Option "Device" "/dev/input/mice" Option "ZAxisMapping" "4 5 6 7" EndSection Section "Monitor" Identifier "Monitor0" VendorName "Monitor Vendor" ModelName "Monitor Model" EndSection Section "Device" ### Available Driver options are:- ### Values: <i>: integer, <f>: float, <bool>: "True"/"False", ### <string>: "String", <freq>: "<f> Hz/kHz/MHz", ### <percent>: "<f>%" ### [arg]: arg optional #Option "SWcursor" # [<bool>] #Option "HWcursor" # [<bool>] #Option "NoAccel" # [<bool>] #Option "ShadowFB" # [<bool>] #Option "VideoKey" # <i> #Option "WrappedFB" # [<bool>] #Option "GLXVBlank" # [<bool>] #Option "ZaphodHeads" # <str> #Option "PageFlip" # [<bool>] #Option "SwapLimit" # <i> #Option "AsyncUTSDFS" # [<bool>] #Option "AccelMethod" # <str> #Option "DRI" # <i> Identifier "Card0" Driver "nouveau" BusID "PCI:1:0:0" EndSection Section "Screen" Identifier "Screen0" Device "Card0" Monitor "Monitor0" SubSection "Display" Viewport 0 0 Depth 1 EndSubSection SubSection "Display" Viewport 0 0 Depth 4 EndSubSection SubSection "Display" Viewport 0 0 Depth 8 EndSubSection SubSection "Display" Viewport 0 0 Depth 15 EndSubSection SubSection "Display" Viewport 0 0 Depth 16 EndSubSection SubSection "Display" Viewport 0 0 Depth 24 EndSubSection EndSection 

My graphics card is Nvidia GeForce 240M.