Installing xRDP on Lubuntu 18.04 broke Xorg on console - how to troubleshoot?

On an out-of-the-box (plus apt update; apt upgrade) Lubuntu 18.04 box, I followed these steps to install xrdp:

sudo apt-get install xrdp
echo 'lxsession -e LXDE -s Lubuntu' > ~/.xsession
sudo service xrdp restart

This worked right away, but it broke Xorg on the console. From another host with Remmina I can still use the system with a complete, 100% functional GUI, but the console remains stuck in text mode (black screen with cursor).

I believe this is a similar scenario to the one outlined in this unanswered 2 year old post.

In /var/log/Xorg.0.log I find:

[    29.206] (II) glamor: OpenGL accelerated X.org driver based.
[    29.232] (II) glamor: EGL version 1.4:
[    29.255] (II) modeset(0): glamor initialized
[    29.264] (II) modeset(0): Output VGA-1 has no monitor section
[    29.271] (II) modeset(0): Output DVI-D-1 has no monitor section
[    29.362] (II) modeset(0): Output SVIDEO-1 has no monitor section
[    29.381] (II) modeset(0): EDID for output VGA-1
[    29.381] (II) modeset(0): Printing probed modes for output VGA-1
[    29.381] (II) modeset(0): Modeline "1024x768"x60.0   65.00  1024 1048 1184 1344  768 771 777 806 -hsync -vsync (48.4 kHz e)
[    29.381] (II) modeset(0): Modeline "800x600"x60.3   40.00  800 840 968 1056  600 601 605 628 +hsync +vsync (37.9 kHz e)
[    29.381] (II) modeset(0): Modeline "800x600"x56.2   36.00  800 824 896 1024  600 601 603 625 +hsync +vsync (35.2 kHz e)
[    29.381] (II) modeset(0): Modeline "848x480"x60.0   33.75  848 864 976 1088  480 486 494 517 +hsync +vsync (31.0 kHz e)
[    29.381] (II) modeset(0): Modeline "640x480"x59.9   25.18  640 656 752 800  480 490 492 525 -hsync -vsync (31.5 kHz e)
[    29.386] (II) modeset(0): EDID for output DVI-D-1
[    29.477] (II) modeset(0): EDID for output SVIDEO-1
[    29.477] (II) modeset(0): Output VGA-1 connected
[    29.478] (II) modeset(0): Output DVI-D-1 disconnected
[    29.478] (II) modeset(0): Output SVIDEO-1 disconnected
[    29.478] (II) modeset(0): Using exact sizes for initial modes
[    29.478] (II) modeset(0): Output VGA-1 using initial mode 1024x768 +0+0
[    29.478] (==) modeset(0): Using gamma correction (1.0, 1.0, 1.0)
[    29.478] (==) modeset(0): DPI set to (96, 96)
[    29.478] (II) Loading sub module "fb"
[    29.478] (II) LoadModule: "fb"
[    29.478] (II) Loading /usr/lib/xorg/modules/libfb.so
[    29.478] (II) Module fb: vendor="X.Org Foundation"
[    29.478]    compiled for 1.19.6, module version = 1.0.0
[    29.479]    ABI class: X.Org ANSI C Emulation, version 0.4
[    29.479] (==) Depth 24 pixmap format is 32 bpp
[    29.479] Require OpenGL version 2.1 or later.
[    29.479] (EE) modeset(0): Failed to initialize glamor at ScreenInit() time.
[    29.479] (EE)
Fatal server error:
[    29.479] (EE) AddScreen/ScreenInit failed for driver 0
[    29.479] (EE)
[    29.479] (EE)
Please consult the The X.Org Foundation support
         at http://wiki.x.org
 for help.
[    29.479] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information.

The 'startx' command on the console outputs the following (typed in manually here because I can't copy-and-paste from the text mode console; there's no mouse support there):

Xorg X Server 1.19.6
Release Date: 2017-12-20
X Protocol Version 11, Revision 0
Build Operating System: Linux 4.15.0-140-generic 1686 Ubuntu
Current Operating System: Linux de945 5.4.0-80-generic #90~18.04.1-Ubuntu SMP Tue Jul 13 19:38:58 UtC 201 i686
Kernel command line: BOOT_IMAGE=/boot/vmliuz-5.4.0-80-generic root=UUID=5e51f27a-0823-4e70-aff8-7c513bc63fb3 ro quiet splash vt.handoff=1
Buil Date: 08 April 2021 01:52:21PM
xorg-server 2:1.19.6-1ubuntu4.9 (For technical support please see http://www.ubuntu.com/support)
Current version of pixman: 0.34.0
Before reporting problems, check http://wiki.x.org to make surethatyou have the latest version.
Marker: (--) probed, (**) from config file, (==) default setting, (**) from command line, (!!) notice, (II) informational, (WW) warning, (EE) error, (NI) not implemented, (??) unknown.
(==) Log file: "/home/frankvw/.local/share/xorg/Xorg.0.log",Time: Mon Jul 26 13:31:18 2021
(==) Using system config directory "/usr/share/X11/xorg.conf.d"
Require OpenGL version 2.1 or later.
(EE) Fatal server error: (EE) AddScreen/ScreenInit failed for driver 0. (EE) Please consult the Xorg Foundation support at http://wiki.x.org for help. (EE) Please also check the log file at "/home/frankvw/.local/share/xorg/Xorg.0.log" for additional information.
(EE) Server terminated with error (1). CLosing logfile.
xinit: giving up
xinit: unable to connect to X server: Connection refused
Xinit: server error

The command glxinfo | grep "OpenGL version" entered from Remmina (on the text mode console I get an "Error: unable to open display) produces OpenGL version string: 3.1 Mesa 20.0.8.

Where do I go from here? How do I find out what has been borked by the xrdp install and where, and how to fix it?

All suggestions are welcome!

// FvW

OK... After much Googling and experimentation, the following solved the problem:

sudo apt install xserver-xorg-video-intel
Xorg :0 -configure
mv /root/xorg.conf.new /usr/share/X11/xorg.conf.d/xorg.conf
sudo apt install xserver-xorg-input-mouse
sudo apt install xserver-xorg-input-kbd

The generation of the xorg.conf.new file resulted in errors; the generated config contained duplicate Monitor, Device and Screen sections. I deleted the second copy of each and at the top of the config I included the following:

Section "ServerFlags"
        Option       "AutoAddDevices"   "false"
EndSection

Reboot. And there was much rejoicing.

This is "brute force' operation, forcing manual rather than probed hardware support, but it's the only thing that yielded any result at all. I/m still not sure what xrdp broke, or where, or how, or why. But this fixed it.