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esphen

Member

Registered: 2015-10-03

Posts: 2

LightDM displays black screen and freezes computer

Hi there!

I have been spending the last couple of days frantically trying to get LightDM to work, and thus far - no luck. When run systemctl start lightdm, the screen turns black, and I see a cursor in the top left that does NOT blink. No manual action works at this point, not even switching tty with ctl + alt + F*. I am forced to smother my computer holding the power button for several seconds.

It would seem like something is wrong with my X setup, but startxfce4 and startx work fine. I could also be missing some obscure package from my install, but I am at a loss what that could be. Not sure where to go from here, any and all help is appreciated.

Here is the output of relevant log and config files:

Relevant config files:

lightdm.log:

[+0.00s] DEBUG: Logging to /var/log/lightdm/lightdm.log
[+0.00s] DEBUG: Starting Light Display Manager 1.16.3, UID=0 PID=1004
[+0.00s] DEBUG: Loading configuration dirs from /usr/share/lightdm/lightdm.conf.d
[+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: Using D-Bus name org.freedesktop.DisplayManager
[+0.00s] DEBUG: Registered seat module xlocal
[+0.00s] DEBUG: Registered seat module xremote
[+0.00s] DEBUG: Registered seat module unity
[+0.00s] DEBUG: Monitoring logind for seats
[+0.00s] DEBUG: New seat added from logind: seat0
[+0.00s] DEBUG: Seat seat0: Loading properties from config section Seat:*
[+0.00s] DEBUG: Seat seat0: Starting
[+0.00s] DEBUG: Seat seat0: Creating greeter session
[+0.01s] DEBUG: Seat seat0: Creating display server of type x
[+0.01s] DEBUG: Could not run plymouth --ping: Failed to execute child process "plymouth" (No such file or directory)
[+0.01s] DEBUG: Using VT 7
[+0.01s] DEBUG: Seat seat0: Starting local X display on VT 7
[+0.01s] DEBUG: DisplayServer x-0: Logging to /var/log/lightdm/x-0.log
[+0.03s] DEBUG: DisplayServer x-0: Writing X server authority to /run/lightdm/root/:0
[+0.03s] DEBUG: DisplayServer x-0: Launching X Server
[+0.03s] DEBUG: Launching process 1009: /usr/sbin/X :0 -seat seat0 -auth /run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
[+0.03s] DEBUG: DisplayServer x-0: Waiting for ready signal from X server :0
[+0.03s] DEBUG: Acquired bus name org.freedesktop.DisplayManager
[+0.03s] DEBUG: Registering seat with bus path /org/freedesktop/DisplayManager/Seat0
[+0.64s] DEBUG: Loading users from org.freedesktop.Accounts
[+0.64s] DEBUG: User /org/freedesktop/Accounts/User1000 added
[+1.27s] DEBUG: Seat seat0 changes active session to 
[+1.27s] CRITICAL: session_get_login1_session_id: assertion 'session != NULL' failed
[+83.30s] DEBUG: Got signal 15 from process 1
[+83.30s] DEBUG: Caught Terminated signal, shutting down
[+83.30s] DEBUG: Stopping display manager
[+83.30s] DEBUG: Seat seat0: Stopping
[+83.30s] DEBUG: Seat seat0: Stopping display server
[+83.30s] DEBUG: Sending signal 15 to process 1009
[+83.30s] DEBUG: Seat seat0: Stopping session
[+83.30s] DEBUG: Seat seat0: Session stopped

x-0.log

X.Org X Server 1.17.2
Release Date: 2015-06-16
X Protocol Version 11, Revision 0
Build Operating System: Linux 4.0.4-2-ARCH x86_64 
Current Operating System: Linux hel 4.2.2-1-ARCH #1 SMP PREEMPT Tue Sep 29 22:21:33 CEST 2015 x86_64
Kernel command line: initrd=\initramfs-linux.img cryptdevice=UUID=0a299dd1-4653-4f3a-92c3-0f05c9a6092d:root root=/dev/mapper/root rw
Build Date: 17 July 2015  05:38:19PM
 
Current version of pixman: 0.32.8
        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: Sat Oct  3 17:15:57 2015
(==) Using system config directory "/usr/share/X11/xorg.conf.d"

I am also posting the x-0-greeter.log and x-0-greeter.log.old below, but I am not sure this is relevant because it does not seem like above logs are getting that far at all. I have had intermittent success running systemctl start lightdm after leaving an xfce session initated with startxfce4, but this is not consistent. I believe this is where these logs are generated and therefore not related to this problem, but feel free to have a look.

x-0-greeter.log:

** (process:1467): WARNING **: Failed to open CK session: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.freedesktop.ConsoleKit was not provided by any .service files
** Message: Starting lightdm-gtk-greeter 2.0.1 (May 26 2015, 08:48:40)
** Message: [Configuration] Reading file: /etc/lightdm/lightdm-gtk-greeter.conf
libGL error: failed to open drm device: Permission denied
libGL error: failed to load driver: nouveau

** (lightdm-gtk-greeter:1541): WARNING **: Failed to flush data to daemon: Broken pipe

x-0-greeter.log.old:

** Message: Starting lightdm-gtk-greeter 2.0.1 (May 26 2015, 08:48:40)
** Message: [Configuration] Reading file: /etc/lightdm/lightdm-gtk-greeter.conf

** (lightdm-gtk-greeter:804): WARNING **: [PIDs] Failed to execute command: upstart

(lightdm-gtk-greeter:804): GLib-GObject-WARNING **: The property GtkWidget:margin-left is deprecated and shouldn't be used anymore. It will be removed in a future version.

(lightdm-gtk-greeter:804): GLib-GObject-WARNING **: The property GtkWidget:margin-right is deprecated and shouldn't be used anymore. It will be removed in a future version.

(lightdm-gtk-greeter:804): GLib-GObject-WARNING **: The property GtkImage:stock is deprecated and shouldn't be used anymore. It will be removed in a future version.

/etc/lightdm/lightdm.conf:

[LightDM]
logind-check-graphical=true
run-directory=/run/lightdm
[Seat:*]
greeter-session=lightdm-gtk-greeter
session-wrapper=/etc/lightdm/Xsession
exit-on-failure=true
[XDMCPServer]
[VNCServer]

Last edited by esphen (2015-10-03 15:51:09)

toni

Member

Registered: 2011-10-15

Posts: 437

Re: LightDM displays black screen and freezes computer

Hi,

I have recently updated linux kernel to last one 4.2.2-1 and now I have the same problem you comment. I am using lightdm as well. Lightdm freezes with a cursor not blinking at the top left corner of the blank screen. No way to change to tty modes using CTRL+Fx or ALT+Fx.
Any ideas what is happening?

Thanks in advance!

toni

Member

Registered: 2011-10-15

Posts: 437

Re: LightDM displays black screen and freezes computer

Hi there!

I have been spending the last couple of days frantically trying to get LightDM to work, and thus far - no luck. When run systemctl start lightdm, the screen turns black, and I see a cursor in the top left that does NOT blink. No manual action works at this point, not even switching tty with ctl + alt + F*. I am forced to smother my computer holding the power button for several seconds.

It would seem like something is wrong with my X setup, but startxfce4 and startx work fine. I could also be missing some obscure package from my install, but I am at a loss what that could be. Not sure where to go from here, any and all help is appreciated.

Here is the output of relevant log and config files:

Relevant config files:

lightdm.log:

[+0.00s] DEBUG: Logging to /var/log/lightdm/lightdm.log
[+0.00s] DEBUG: Starting Light Display Manager 1.16.3, UID=0 PID=1004
[+0.00s] DEBUG: Loading configuration dirs from /usr/share/lightdm/lightdm.conf.d
[+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: Using D-Bus name org.freedesktop.DisplayManager
[+0.00s] DEBUG: Registered seat module xlocal
[+0.00s] DEBUG: Registered seat module xremote
[+0.00s] DEBUG: Registered seat module unity
[+0.00s] DEBUG: Monitoring logind for seats
[+0.00s] DEBUG: New seat added from logind: seat0
[+0.00s] DEBUG: Seat seat0: Loading properties from config section Seat:*
[+0.00s] DEBUG: Seat seat0: Starting
[+0.00s] DEBUG: Seat seat0: Creating greeter session
[+0.01s] DEBUG: Seat seat0: Creating display server of type x
[+0.01s] DEBUG: Could not run plymouth --ping: Failed to execute child process "plymouth" (No such file or directory)
[+0.01s] DEBUG: Using VT 7
[+0.01s] DEBUG: Seat seat0: Starting local X display on VT 7
[+0.01s] DEBUG: DisplayServer x-0: Logging to /var/log/lightdm/x-0.log
[+0.03s] DEBUG: DisplayServer x-0: Writing X server authority to /run/lightdm/root/:0
[+0.03s] DEBUG: DisplayServer x-0: Launching X Server
[+0.03s] DEBUG: Launching process 1009: /usr/sbin/X :0 -seat seat0 -auth /run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
[+0.03s] DEBUG: DisplayServer x-0: Waiting for ready signal from X server :0
[+0.03s] DEBUG: Acquired bus name org.freedesktop.DisplayManager
[+0.03s] DEBUG: Registering seat with bus path /org/freedesktop/DisplayManager/Seat0
[+0.64s] DEBUG: Loading users from org.freedesktop.Accounts
[+0.64s] DEBUG: User /org/freedesktop/Accounts/User1000 added
[+1.27s] DEBUG: Seat seat0 changes active session to 
[+1.27s] CRITICAL: session_get_login1_session_id: assertion 'session != NULL' failed
[+83.30s] DEBUG: Got signal 15 from process 1
[+83.30s] DEBUG: Caught Terminated signal, shutting down
[+83.30s] DEBUG: Stopping display manager
[+83.30s] DEBUG: Seat seat0: Stopping
[+83.30s] DEBUG: Seat seat0: Stopping display server
[+83.30s] DEBUG: Sending signal 15 to process 1009
[+83.30s] DEBUG: Seat seat0: Stopping session
[+83.30s] DEBUG: Seat seat0: Session stopped

x-0.log

X.Org X Server 1.17.2
Release Date: 2015-06-16
X Protocol Version 11, Revision 0
Build Operating System: Linux 4.0.4-2-ARCH x86_64 
Current Operating System: Linux hel 4.2.2-1-ARCH #1 SMP PREEMPT Tue Sep 29 22:21:33 CEST 2015 x86_64
Kernel command line: initrd=\initramfs-linux.img cryptdevice=UUID=0a299dd1-4653-4f3a-92c3-0f05c9a6092d:root root=/dev/mapper/root rw
Build Date: 17 July 2015  05:38:19PM
 
Current version of pixman: 0.32.8
        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: Sat Oct  3 17:15:57 2015
(==) Using system config directory "/usr/share/X11/xorg.conf.d"

I am also posting the x-0-greeter.log and x-0-greeter.log.old below, but I am not sure this is relevant because it does not seem like above logs are getting that far at all. I have had intermittent success running systemctl start lightdm after leaving an xfce session initated with startxfce4, but this is not consistent. I believe this is where these logs are generated and therefore not related to this problem, but feel free to have a look.

x-0-greeter.log:

** (process:1467): WARNING **: Failed to open CK session: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.freedesktop.ConsoleKit was not provided by any .service files
** Message: Starting lightdm-gtk-greeter 2.0.1 (May 26 2015, 08:48:40)
** Message: [Configuration] Reading file: /etc/lightdm/lightdm-gtk-greeter.conf
libGL error: failed to open drm device: Permission denied
libGL error: failed to load driver: nouveau

** (lightdm-gtk-greeter:1541): WARNING **: Failed to flush data to daemon: Broken pipe

x-0-greeter.log.old:

** Message: Starting lightdm-gtk-greeter 2.0.1 (May 26 2015, 08:48:40)
** Message: [Configuration] Reading file: /etc/lightdm/lightdm-gtk-greeter.conf

** (lightdm-gtk-greeter:804): WARNING **: [PIDs] Failed to execute command: upstart

(lightdm-gtk-greeter:804): GLib-GObject-WARNING **: The property GtkWidget:margin-left is deprecated and shouldn't be used anymore. It will be removed in a future version.

(lightdm-gtk-greeter:804): GLib-GObject-WARNING **: The property GtkWidget:margin-right is deprecated and shouldn't be used anymore. It will be removed in a future version.

(lightdm-gtk-greeter:804): GLib-GObject-WARNING **: The property GtkImage:stock is deprecated and shouldn't be used anymore. It will be removed in a future version.

/etc/lightdm/lightdm.conf:

[LightDM]
logind-check-graphical=true
run-directory=/run/lightdm
[Seat:*]
greeter-session=lightdm-gtk-greeter
session-wrapper=/etc/lightdm/Xsession
exit-on-failure=true
[XDMCPServer]
[VNCServer]

Have you tried another desktop manager like gdm?

You can do a chrooting and uninstall lightdm and reinstall it again or even substitute it with another one like gdm, then reboot. Note that in chrooting mode you cannot perform any systemctl enable/disable command or similar.

If it does not work you can chrooting into your system and uninstall any desktop manager (and not install any one), then reboot and it will enter direclty in console mode.

Once in console mode, install any desktop manager again (lightdm, gdm, etc.) and then, try to recreate your display-manger.service symlink using below command (It is highly recommended when switching between desktop managers):
(see "Failed to issue method call: File exists" error)

#systemctl -f enable gdm.service (if you use gdm)

or

#systemctl -f enable lightdm.service (if you use lightdm)

I changed to gdm and recreate the desktop manger symlink and now it is working for me.

Hope it helps.

Last edited by toni (2015-10-04 08:15:17)

esphen

Member

Registered: 2015-10-03

Posts: 2

Re: LightDM displays black screen and freezes computer

I uninstalled LightDM, and GDM seems to work. That is slightly disappointing - I wanted to try something new; all my other machines are on GDM. It seems I will have to stick with GDM for now unless anyone has any suggestions.

Thanks for the tip, toni

toni

Member

Registered: 2011-10-15

Posts: 437

Re: LightDM displays black screen and freezes computer

I uninstalled LightDM, and GDM seems to work. That is slightly disappointing - I wanted to try something new; all my other machines are on GDM. It seems I will have to stick with GDM for now unless anyone has any suggestions.

Thanks for the tip, toni

Once you installed LightDM, did you install a greeter as well? You can use lightDM without a greeter only if you have configured an automatic login. Otherwise you need to install a greeter for lightDM like lightdm-gtk-greeter

Also you need to enable lightDM service so it can start at boot:

# systemctl enable lightdm.service

See more information here

lemel

Member

Registered: 2015-09-13

Posts: 3

Re: LightDM displays black screen and freezes computer

I uninstalled LightDM, and GDM seems to work. That is slightly disappointing - I wanted to try something new; all my other machines are on GDM. It seems I will have to stick with GDM for now unless anyone has any suggestions.

Thanks for the tip, toni

Once you installed LightDM, did you install a greeter as well? You can use lightDM without a greeter only if you have configured an automatic login. Otherwise you need to install a greeter for lightDM like lightdm-gtk-greeter

Also you need to enable lightDM service so it can start at boot:

# systemctl enable lightdm.service

See more information here

I had the same problem recently as the OP, had to switch to gdm. I think the problem is the new version of lightdm 1.16.
It started after updated from lightdm-devel 1.15 from AUR to lightdm 1.16 (from pacman, supposedly stable version).
The problem is that the lightdm service doesn't even start, even if it was enabled. I had plymouth installed so thought it might be the problem.
Uninstalled plymouth, reinstalled lightdm 1.16, and I still have the same problem.
I had to re-enable and assign gdm as the default display manager.
It's a shame as I was using gnome-flashback with compiz, now back to gnome classic with gdm.

Here is the log from

systemctl status lightdm.service

● lightdm.service - Light Display Manager
   Loaded: loaded (/usr/lib/systemd/system/lightdm.service; disabled; vendor preset: disabled)
   Active: failed (Result: start-limit) since Tue 2015-10-06 22:35:38 CEST; 11s ago
     Docs: man:lightdm(1)
  Process: 3927 ExecStart=/usr/bin/lightdm (code=exited, status=1/FAILURE)
 Main PID: 3927 (code=exited, status=1/FAILURE)

Oct 06 22:35:38 cosmos systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Oct 06 22:35:38 cosmos systemd[1]: Failed to start Light Display Manager.
Oct 06 22:35:38 cosmos systemd[1]: lightdm.service: Unit entered failed state.
Oct 06 22:35:38 cosmos systemd[1]: lightdm.service: Failed with result 'exit-code'.
Oct 06 22:35:38 cosmos systemd[1]: lightdm.service: Service hold-off time over, scheduling restart.
Oct 06 22:35:38 cosmos systemd[1]: Stopped Light Display Manager.
Oct 06 22:35:38 cosmos systemd[1]: lightdm.service: Start request repeated too quickly.
Oct 06 22:35:38 cosmos systemd[1]: Failed to start Light Display Manager.
Oct 06 22:35:38 cosmos systemd[1]: lightdm.service: Unit entered failed state.
Oct 06 22:35:38 cosmos systemd[1]: lightdm.service: Failed with result 'start-limit'.

and here is the result from

journalctl -xe

Oct 06 22:49:52 cosmos sudo[4015]:      mel : TTY=pts/0 ; PWD=/home/mel ; USER=root ; COMMAND=/usr/bin/systemctl start lightdm.service
Oct 06 22:49:52 cosmos sudo[4015]: pam_unix(sudo:session): session opened for user root by mel(uid=0)
Oct 06 22:49:52 cosmos systemd[1]: Starting Light Display Manager...
-- Subject: Unit lightdm.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit lightdm.service has begun starting up.
Oct 06 22:49:52 cosmos polkitd[468]: Registered Authentication Agent for unix-process:4016:564374 (system bus name :1.177 [/usr/bin/pkttyagent --notif
Oct 06 22:49:52 cosmos systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Oct 06 22:49:52 cosmos systemd[1]: Failed to start Light Display Manager.
-- Subject: Unit lightdm.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit lightdm.service has failed.
-- 
-- The result is failed.
Oct 06 22:49:52 cosmos systemd[1]: lightdm.service: Unit entered failed state.
Oct 06 22:49:52 cosmos systemd[1]: lightdm.service: Failed with result 'exit-code'.
Oct 06 22:49:52 cosmos sudo[4015]: pam_unix(sudo:session): session closed for user root
Oct 06 22:49:53 cosmos polkitd[468]: Unregistered Authentication Agent for unix-process:4016:564374 (system bus name :1.177, object path /org/freedesk
Oct 06 22:49:53 cosmos systemd[1]: lightdm.service: Service hold-off time over, scheduling restart.
Oct 06 22:49:53 cosmos systemd[1]: Stopped Light Display Manager.
-- Subject: Unit lightdm.service has finished shutting down
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit lightdm.service has finished shutting down.
Oct 06 22:49:53 cosmos systemd[1]: Starting Light Display Manager...
-- Subject: Unit lightdm.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit lightdm.service has begun starting up.
Oct 06 22:49:53 cosmos systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Oct 06 22:49:53 cosmos systemd[1]: Failed to start Light Display Manager.
-- Subject: Unit lightdm.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit lightdm.service has failed.
-- 
-- The result is failed.
Oct 06 22:49:53 cosmos systemd[1]: lightdm.service: Unit entered failed state.
Oct 06 22:49:53 cosmos systemd[1]: lightdm.service: Failed with result 'exit-code'.
Oct 06 22:49:53 cosmos systemd[1]: lightdm.service: Service hold-off time over, scheduling restart.
Oct 06 22:49:53 cosmos systemd[1]: Stopped Light Display Manager.
-- Subject: Unit lightdm.service has finished shutting down
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit lightdm.service has finished shutting down.
Oct 06 22:49:53 cosmos systemd[1]: Starting Light Display Manager...
-- Subject: Unit lightdm.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit lightdm.service has begun starting up.
Oct 06 22:49:53 cosmos systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Oct 06 22:49:53 cosmos systemd[1]: Failed to start Light Display Manager.
-- Subject: Unit lightdm.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit lightdm.service has failed.
-- 
-- The result is failed.
Oct 06 22:49:53 cosmos systemd[1]: lightdm.service: Unit entered failed state.
Oct 06 22:49:53 cosmos systemd[1]: lightdm.service: Failed with result 'exit-code'.
Oct 06 22:49:53 cosmos systemd[1]: lightdm.service: Service hold-off time over, scheduling restart.
Oct 06 22:49:53 cosmos systemd[1]: Stopped Light Display Manager.
-- Subject: Unit lightdm.service has finished shutting down
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit lightdm.service has finished shutting down.
Oct 06 22:49:53 cosmos systemd[1]: Starting Light Display Manager...
-- Subject: Unit lightdm.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit lightdm.service has begun starting up.
Oct 06 22:49:53 cosmos systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Oct 06 22:49:53 cosmos systemd[1]: Failed to start Light Display Manager.
-- Subject: Unit lightdm.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit lightdm.service has failed.
-- 
-- The result is failed.
Oct 06 22:49:53 cosmos systemd[1]: lightdm.service: Unit entered failed state.
Oct 06 22:49:53 cosmos systemd[1]: lightdm.service: Failed with result 'exit-code'.
Oct 06 22:49:53 cosmos systemd[1]: lightdm.service: Service hold-off time over, scheduling restart.
Oct 06 22:49:53 cosmos systemd[1]: Stopped Light Display Manager.
-- Subject: Unit lightdm.service has finished shutting down
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit lightdm.service has finished shutting down.
Oct 06 22:49:53 cosmos systemd[1]: Starting Light Display Manager...
-- Subject: Unit lightdm.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit lightdm.service has begun starting up.
Oct 06 22:49:53 cosmos systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Oct 06 22:49:53 cosmos systemd[1]: Failed to start Light Display Manager.
-- Subject: Unit lightdm.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit lightdm.service has failed.
-- 
-- The result is failed.
Oct 06 22:49:53 cosmos systemd[1]: lightdm.service: Unit entered failed state.
Oct 06 22:49:53 cosmos systemd[1]: lightdm.service: Failed with result 'exit-code'.
Oct 06 22:49:54 cosmos systemd[1]: lightdm.service: Service hold-off time over, scheduling restart.
Oct 06 22:49:54 cosmos systemd[1]: Stopped Light Display Manager.
-- Subject: Unit lightdm.service has finished shutting down
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit lightdm.service has finished shutting down.
Oct 06 22:49:54 cosmos systemd[1]: lightdm.service: Start request repeated too quickly.
Oct 06 22:49:54 cosmos systemd[1]: Failed to start Light Display Manager.
-- Subject: Unit lightdm.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit lightdm.service has failed.
-- 
-- The result is failed.
Oct 06 22:49:54 cosmos systemd[1]: lightdm.service: Unit entered failed state.
Oct 06 22:49:54 cosmos systemd[1]: lightdm.service: Failed with result 'start-limit'.

Aakko

Member

Registered: 2007-10-23

Posts: 65

Re: LightDM displays black screen and freezes computer

I have exactly the same problem as lemel.

After pacman -Syu LightDM stopped working.

satanselbow

Member

Registered: 2011-06-15

Posts: 538

Re: LightDM displays black screen and freezes computer

I suffered the same fate and resorted to manually "cleaning" the remnants of lightdm after removing before reinstalling light{dm, dm-gtk-greeter, dm-gtk-greeter-settings, -locker}

The following folders were nuked after -Rns:

# rm -R /etc/lightdm
# rm -R /var/lib/lightdm
# rm -R /var/lib/lightdm-data
# rm -R /usr/lib/python3.5/site-packages/lightdm_gtk_greeter_settings

Unscientific... but effective.

LightDM is now working as it should in it's default config - I have not, as yet, reimplemented any further customisations.

**********
UPDATE

***********

The latest lightdm doesn't seem to like older GTK2 themes (FlatStudioDark in my case) - GTK3 only by the looks of it

Last edited by satanselbow (2015-10-12 09:20:01)

toni

Member

Registered: 2011-10-15

Posts: 437

Re: LightDM displays black screen and freezes computer

Hi, again!
I have tried to install lightdm again but without success.

In my case, I log in into virtual terminal tty1 directly. X does not start.
When I start it manually by performing:

# systemctl start lightdm.service

A black screen is shown and a cursor blinking on the top left corner but I can return to virtual terminal tty1 again.

I have opened a different thread as in my case lightdm does not freezes at all since I can return to tty1 and investigate.

See my thread here

dtw

Forum Fellow

From: UK

Registered: 2004-08-03

Posts: 4,439

Website

Re: LightDM displays black screen and freezes computer

The latest lightdm doesn't seem to like older GTK2 themes (FlatStudioDark in my case) - GTK3 only by the looks of it

That's the exact theme I am using. I can't get mine to start either.

Ah, I disabled that theme and it works fine now.

Last edited by dtw (2015-10-20 21:35:57)

firekage

Member

From: Eastern Europe, Poland

Registered: 2013-06-30

Posts: 619

Re: LightDM displays black screen and freezes computer

The latest lightdm doesn't seem to like older GTK2 themes (FlatStudioDark in my case) - GTK3 only by the looks of it

That's the exact theme I am using. I can't get mine to start either.

Ah, I disabled that theme and it works fine now.

Out of curiosity - how did you change it after not being able to start lightdm?

satanselbow

Member

Registered: 2011-06-15

Posts: 538

Re: LightDM displays black screen and freezes computer

I was able to reach another tty and commented out the theme with nano. I was not experiencing the "hard lock" just the black screen / blinking cursor.

toni

Member

Registered: 2011-10-15

Posts: 437

Re: LightDM displays black screen and freezes computer

In my case I think I am not using old GTK2 themes but I have solved partially.

My problem was that xf86-video-intel package was not installed so I have installed it from repository xorg116 (as catalyst-total 15.9-2 is only compatible with xorg-server < 1.17).
After installing it, X does not start automatically but I can now force lightdm to start (see below).

When performing below command:

$ systemctl status lightdm.service

It shows as loaded but inactive.

Anyway, now I can restart X by doing:

$ systemctl start lightdm.service

and then lightdm starts, I can login and reach to X

Also I can switch between discrete (AMD) or integrated (Intel) video cards by using below commands:

AMD:

$ sudo aticonfig --px-dgpu

Intel:

$ sudo aticonfig --px-igpu

Also, adding "nomodeset i915.modeset=0" as a kernel parameter as Arch Wiki says is not working for me so I have to remove them.
I am using LTS kernel.

Last edited by toni (2015-10-21 22:36:18)

0xADADA

Member

From: ██████, MA, USA

Registered: 2016-03-08

Posts: 8

Website

Re: LightDM displays black screen and freezes computer

I'm having this same problem, the a black screen, non-blinking cursor in the top-left, and have to hard-reboot to regain any control. Cannot even switch TTYS.