Gdm3 login fail with both gnome(wayland) & gnome on xorg; only the gnome classic session can be opened. Installing lightdm AND ubuntu-session seem solving the issue, but still not real wayland session, even when loging with 'gnome' (x11 detected by xdg).
The graphic chipset is an intel igpu 530 (skylake gt2) and has previously smootly worked with wayland some times ago into Artfull. Now i have the feeling that someting detect that hardware not able to use wayland, and so decide to go thru the Xorg fallback mechanism, which is wrong indeed. Note that system only have that igpu chipset, no additional graphic card.
When a wayland session is selected from the dropdown login list, in fact the selection is not done (checked by a second gear click) and the login script automatically select the 'xorg' choice (either gnome or ubuntu).
journalctl has logged:
/usr/lib/gdm3/gdm-x-session[1060]: /etc/gdm3/Xsession: Beginning session setup...
/usr/lib/gdm3/gdm-x-session[1060]: This is BASH 4.4 - DISPLAY on :0
/usr/lib/gdm3/gdm-x-session[1060]: Sat Nov 11 11:15:16 CET 2017
/usr/lib/gdm3/gdm-x-session[1060]: localuser:oem being added to access control list
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting DISPLAY=:0
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting XAUTHORITY=/run/user/1000/gdm/Xauthority
/usr/lib/gdm3/gdm-x-session[1060]: localuser:oem being added to access control list
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting GTK_MODULES=gail:atk-bridge
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting QT_ACCESSIBILITY=1
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting CLUTTER_IM_MODULE=xim
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting LC_ALL=fr_FR.UTF-8
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting LC_MEASUREMENT=en_US.UTF-8
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting LC_PAPER=en_US.UTF-8
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting LC_MONETARY=en_US.UTF-8
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting LANG=en_US.UTF-8
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting HISTIGNORE=&
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting HISTCONTROL=erasedups
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting LESS=-i -N -w -z-4 -g -e -M -X -F -R -P%t?f%f \
/usr/lib/gdm3/gdm-x-session[1060]: :stdin .?pb%pb\%:?lbLine %lb:?bbByte %bb:-...
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting DISPLAY=:0
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting USERNAME=oem
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting MANDATORY_PATH=/usr/share/gconf/gnome-xorg.mandatory.path
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting LC_NAME=en_US.UTF-8
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting USER=oem
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting PAGER=less
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting DESKTOP_SESSION=gnome-xorg
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting QT4_IM_MODULE=xim
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting TEXTDOMAINDIR=/usr/share/locale/
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting DEFAULTS_PATH=/usr/share/gconf/gnome-xorg.default.path
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting PWD=/home/oem
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting HOME=/home/oem
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting JOURNAL_STREAM=9:26157
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting TEXTDOMAIN=im-config
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting QT_ACCESSIBILITY=1
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting TIMEFORMAT=
/usr/lib/gdm3/gdm-x-session[1060]: real %3R user %3U sys %3S pcpu %P
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting XDG_SESSION_TYPE=x11
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting XDG_DATA_DIRS=/usr/share/gnome-xorg:/usr/share/gnome:/usr/share/gnome-xorg:/usr/local/share:/usr/share:/var/lib/snapd/desktop
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting XDG_SESSION_DESKTOP=gnome-xorg
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting LC_ADDRESS=en_US.UTF-8
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting LC_NUMERIC=en_US.UTF-8
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting GTK_MODULES=gail:atk-bridge
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting PAPERSIZE=letter
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting WINDOWPATH=2
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting SHELL=/bin/bash
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting QT_IM_MODULE=ibus
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting XMODIFIERS=@im=ibus
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting IM_CONFIG_PHASE=2
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting XDG_CURRENT_DESKTOP=GNOME
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting SHLVL=1
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting LANGUAGE=en_US:en
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting LC_TELEPHONE=en_US.UTF-8
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting GDMSESSION=gnome-xorg
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting LESSCHARSET=latin1
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting LOGNAME=oem
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting XDG_RUNTIME_DIR=/run/user/1000
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting HOSTFILE=/home/oem/.hosts
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting XAUTHORITY=/run/user/1000/gdm/Xauthority
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting XDG_CONFIG_DIRS=/etc/xdg/xdg-gnome-xorg:/etc/xdg/xdg-gnome-xorg:/etc/xdg
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting PATH=/home/oem/bin:/sbin:/usr/sbin:/usr/local/sbin:/usr/local/bin:/usr/bin:/bin:/usr/games:/usr/local/games
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting LC_IDENTIFICATION=en_US.UTF-8
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting LESSOPEN=|/usr/bin/lesspipe.sh %s 2>&-
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting GTK_IM_MODULE=ibus
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting LC_TIME=en_US.UTF-8
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: setting _=/usr/bin/dbus-update-activation-environment
/usr/lib/gdm3/gdm-x-session[1060]: dbus-update-activation-environment: warning: error sending to systemd: org.freedesktop.DBus.Error.InvalidArgs: Invalid environment assignments
...
/usr/lib/gdm3/gdm-x-session[1267]: The XKEYBOARD keymap compiler (xkbcomp) reports:
/usr/lib/gdm3/gdm-x-session[1267]: > Warning: Symbol map for key <NMLK> redefined
/usr/lib/gdm3/gdm-x-session[1267]: > Using last definition for conflicting fields
/usr/lib/gdm3/gdm-x-session[1267]: > Warning: Symbol map for key <KPEN> redefined
/usr/lib/gdm3/gdm-x-session[1267]: > Using last definition for conflicting fields
/usr/lib/gdm3/gdm-x-session[1267]: > Warning: Symbol map for key <KPEQ> redefined
/usr/lib/gdm3/gdm-x-session[1267]: > Using last definition for conflicting fields
/usr/lib/gdm3/gdm-x-session[1267]: Errors from xkbcomp are not fatal to the X server
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gnome-session 3.26.1-0ubuntu7
ProcVersionSignature: Ubuntu 4.13.0-16.19-generic 4.13.4
Uname: Linux 4.13.0-16-generic x86_64
ApportVersion: 2.20.7-0ubuntu4
Architecture: amd64
CurrentDesktop: GNOME-Classic:GNOME
Date: Sat Nov 11 11:25:56 2017
SourcePackage: gnome-session
UpgradeStatus: No upgrade log present (probably fresh install)
Status changed to 'Confirmed' because the bug affects multiple users.