Great! I think I understand the problem now.
The problem is that the Linux kernel is telling us there are two
displays:
LVDS - a laptop display that does not exist
VGA - your real monitor
And then due to bug 1760849, gdm3 is putting the login screen on that
laptop display which doesn't really exist.
A fix for bug 1760849 would suffice. But let's keep this bug open and
make this bug just about the kernel bug of reporting an LVDS output
which doesn't exist.
** Summary changed:
- No login screen displayed on a NETBOX nT-435/535
+ No login screen displayed on a NETBOX nT-435/535 (kernel reports an LVDS
output which does not exist as connected and on)
** Package changed: mutter (Ubuntu) => linux (Ubuntu)
** Changed in: linux (Ubuntu)
Status: Incomplete => New
** No longer affects: gdm3 (Ubuntu)
** No longer affects: gnome-shell (Ubuntu)
** Description changed:
- I've tried the solution mentioned here
- https://bugs.launchpad.net/ubuntu/+source/mutter/+bug/1727356/comments/72
- but it did not solve my issue.
+ On a machine with only one display (VGA), the kernel is reporting two:
+
+ grep . /sys/class/drm/*/enabled
+
+/sys/class/drm/card0-LVDS-1/enabled:enabled
+/sys/class/drm/card0-VGA-1/enabled:enabled
+
+ ls /sys/class/drm
+
+card0 card0-LVDS-1 card0-VGA-1 renderD128 version
+
+ grep . /sys/class/drm/*/dpms
+
+/sys/class/drm/card0-LVDS-1/dpms:On
+/sys/class/drm/card0-VGA-1/dpms:On
+
+ which then triggers bug 1760849 and the login screen is never visible.
+
+ ---
$ dpkg -s mutter
Package: mutter
Status: install ok installed
Priority: optional
Section: x11
Installed-Size: 101
Maintainer: Ubuntu Developers
Architecture: amd64
Version: 3.28.3-2~ubuntu18.04.2
Provides: x-window-manager
Depends: libc6 (>= 2.4), libglib2.0-0 (>= 2.53.2), libmutter-2-0 (>= 3.28.2),
libx11-6, libxcomposite1 (>= 1:0.3-1), mutter-common (>=
3.28.3-2~ubuntu18.04.2), gnome-settings-daemon, gsettings-desktop-schemas (>=
3.21.4), zenity
Suggests: gnome-control-center (>= 1:3.25.2), xdg-user-dirs
Description: lightweight GTK+ window manager
- Mutter is a small window manager, using GTK+ and Clutter to do
- everything.
- .
- Mutter is the clutter-based evolution of Metacity, which, as the
- author says, is a "Boring window manager for the adult in you. Many
- window managers are like Marshmallow Froot Loops; Metacity is like
- Cheerios."
- .
- This package contains the core binaries.
+ Mutter is a small window manager, using GTK+ and Clutter to do
+ everything.
+ .
+ Mutter is the clutter-based evolution of Metacity, which, as the
+ author says, is a "Boring window manager for the adult in you. Many
+ window managers are like Marshmallow Froot Loops; Metacity is like
+ Cheerios."
+ .
+ This package contains the core binaries.
Original-Maintainer: Debian GNOME Maintainers
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: mutter 3.28.3-2~ubuntu18.04.2
ProcVersionSignature: Ubuntu 4.15.0-43.46-generic 4.15.18
Uname: Linux 4.15.0-43-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Fri Jan 18 15:02:22 2019
InstallationDate: Installed on 2019-01-18 (0 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
ProcEnviron:
- TERM=xterm-256color
- PATH=(custom, no user)
- XDG_RUNTIME_DIR=
- LANG=en_IN
- SHELL=/bin/bash
+ TERM=xterm-256color
+ PATH=(custom, no user)
+ XDG_RUNTIME_DIR=
+ LANG=en_IN
+ SHELL=/bin/bash
SourcePackage: mutter
UpgradeStatus: No upgrade log present (probably fresh install)
--
You received this bug notification because you are a member of Ubuntu
Desktop Bugs, which is subscribed to gdm3 in Ubuntu.
https://bugs.launchpad.net/bugs/1812359
Title:
No login screen displayed on a NETBOX nT-435/535 (kernel reports an
LVDS output which does not exist as connected and on)
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https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1812359/+subscriptions
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