Error cannot open display: :0.0. Need to kill xfce4-session

PingouinDuNord · 2021-12-11 22:20:05

Hello,

I have a strange issue where no program can start after login to my session.
After the boot, LightDM starts as expected and I can log into my session.
Then xfce4 starts correctly showing my panel with the launcher and plugins.
If I place my pointer over an icon in the launcher area or navigate through the applications menu, I can see an overlay. And when clicking on the icon (i.e: Firefox, terminal, vlc or xed) I have a spinning pointer for a fraction of a second but nothing appears on screen (no window or pop-up). It is also impossible to start a terminal with Ctrl+Alt+T.

My only solution is to go to ttyX (Ctrl+Alt+FX) run top and kill xfce4-session.
LightDM will appear again.
After login again, xfce4 starts without issue and works fine (I can start any program I want).

I would like to understand what's wrong with the first login.

During the failing phase, I found that I can open a terminal (Ctrl+Alt+T) right after the login. If I try to start a program such as Firefox or Xed, I got the following message:

error cannot open display: :0.0

The only thing I did was to update my Windows 10 and install wsl in order to access an ext4 partition on windows.
I uninstalled wsl but it didn't fix anything.
[Edit] I also did a full update with yay -Syu

OS: Dual boot Arch + Windows 10 on ntfs partition
DM: LightDM
XFCE4
Hardware: T440p

Does anyone have an idea of what's going on or what I could do to investigate more?
Is there a way to "repair" xfce4 if it is the source of the issue?

Last edited by PingouinDuNord (2021-12-11 22:50:25)

ToZ · 2021-12-11 22:33:01

When in "failing phase", what does the following return?

ps -ef | grep xf

You can try clearing your sessions cache to see if that helps. While not logged into Xfce, delete the contents of ~/.cache/sessions.

PingouinDuNord · 2021-12-11 22:55:19

Thanks for the reply.

I already tried without success to delete my sessions cache before login from tty1 with the following command:

rm -rf ~/.cache/sessions

I'll try what you are proposing.

From my search I found that some people get the same issue because of networkmanager messing up the hostname:
https://bbs.archlinux.org/viewtopic.php?id=108562
https://bbs.archlinux.org/viewtopic.php?id=118219
I need to find a way to reset the hostname when I'm on WiFi

ToZ · 2021-12-11 23:13:01

What does the following return?

hostnamectl

If unset, you can set it with these instructions

PingouinDuNord · 2021-12-11 23:15:10

Here is the result of the proposed command during the failing phase:

ps -ef | grep xf
arthos       593     577  0 23:04 ?        00:00:00 xfce4-session
arthos       628     586  0 23:04 ?        00:00:00 /usr/lib/xfce4/xfconf/xfconfd
arthos       652     586  0 23:04 ?        00:00:00 /usr/bin/xfce4-screensaver
arthos       666     593  1 23:04 ?        00:00:01 xfwm4
arthos       673     593  0 23:04 ?        00:00:00 xfsettingsd
arthos       683     593  0 23:04 ?        00:00:00 xfce4-panel
arthos       692     593  0 23:04 ?        00:00:00 xfdesktop
arthos       695     683  0 23:04 ?        00:00:00 /usr/lib/xfce4/panel/wrapper-2.0 /usr/lib/xfce4/panel/plugins/libthunar-tpa.so 27 18874375 thunar-tpa Wastebasket Applet Display the Wastebasket
arthos       697     683  0 23:04 ?        00:00:00 /usr/lib/xfce4/panel/wrapper-2.0 /usr/lib/xfce4/panel/plugins/libmount.so 24 18874376 xfce4-mount-plugin Mount devices Shows all mountable devices and (un)mounts them on request.
arthos       698     683  0 23:04 ?        00:00:00 /usr/lib/xfce4/panel/wrapper-2.0 /usr/lib/xfce4/panel/plugins/libcpugraph.so 22 18874377 cpugraph CPU Graph Graphical representation of the CPU load
arthos       699     683  0 23:04 ?        00:00:00 /usr/lib/xfce4/panel/wrapper-2.0 /usr/lib/xfce4/panel/plugins/libxfce4-sensors-plugin.so 29 18874378 xfce4-sensors-plugin Sensor plugin Show sensor values.
arthos       701     683  0 23:04 ?        00:00:00 /usr/lib/xfce4/panel/wrapper-2.0 /usr/lib/xfce4/panel/plugins/libnetload.so 25 18874379 netload Network Monitor Show network traffic
arthos       702     683  0 23:04 ?        00:00:00 /usr/lib/xfce4/panel/wrapper-2.0 /usr/lib/xfce4/panel/plugins/libwavelan.so 28 18874380 wavelan Wavelan View the status of a wireless network
arthos       705     683  0 23:04 ?        00:00:00 /usr/lib/xfce4/panel/wrapper-2.0 /usr/lib/xfce4/panel/plugins/libsystray.so 6 18874382 systray Status Tray Plugin Provides status notifier items (application indicators) and legacy systray items
arthos       706     683  0 23:04 ?        00:00:00 /usr/lib/xfce4/panel/wrapper-2.0 /usr/lib/xfce4/panel/plugins/libpulseaudio-plugin.so 8 18874383 pulseaudio PulseAudio Plugin Adjust the audio volume of the PulseAudio sound system
arthos       707     683  0 23:04 ?        00:00:00 /usr/lib/xfce4/panel/wrapper-2.0 /usr/lib/xfce4/panel/plugins/libxfce4powermanager.so 9 18874384 power-manager-plugin Power Manager Plugin Display the battery levels of your devices and control the brightness of your display
arthos       714     683  0 23:04 ?        00:00:00 /usr/lib/xfce4/panel/wrapper-2.0 /usr/lib/xfce4/panel/plugins/libnotification-plugin.so 10 18874385 notification-plugin Notification Plugin Notification plugin for the Xfce panel
arthos       726     683  0 23:04 ?        00:00:00 /usr/lib/xfce4/panel/wrapper-2.0 /usr/lib/xfce4/panel/plugins/libscreenshooterplugin.so 26 18874386 screenshooter Screenshot Take screenshots of the entire screen, of the active window or of a region
arthos       729     683  0 23:04 ?        00:00:00 /usr/lib/xfce4/panel/wrapper-2.0 /usr/lib/xfce4/panel/plugins/libactions.so 14 18874387 actions Action Buttons Log out, lock or other system actions
arthos       763     593  0 23:04 ?        00:00:00 xfce4-clipman
arthos       765     593  0 23:04 ?        00:00:00 xfce4-power-manager
arthos       772     593  0 23:04 ?        00:00:00 /usr/lib/xfce4/notifyd/xfce4-notifyd
arthos       880       1  1 23:04 ?        00:00:01 /usr/bin/xfce4-terminal
arthos       995     906  0 23:06 pts/0    00:00:00 grep xf

I added localhost definition in my /etc/hosts:

(base) [arthos@DESKTOP-DOP7CJE ~]$ getent hosts
127.0.0.1       localhost
127.0.0.1       localhost

And here is the result of

 (base) [arthos@DESKTOP-DOP7CJE ~]$ hostnamectl 
   Static hostname: n/a                             
Transient hostname: DESKTOP-DOP7CJE.lan
         Icon name: computer-laptop
           Chassis: laptop
        Machine ID: b6091440406e4500a1a4dc5f008b4cef
           Boot ID: 7cd344b5d278498c90ae7f3baf906424
  Operating System: Arch Linux                      
            Kernel: Linux 5.15.7-arch1-1
      Architecture: x86-64
   Hardware Vendor: Lenovo
    Hardware Model: ThinkPad T440p

ToZ · 2021-12-11 23:26:46

Yes, you don't have a hostname set. Follow the instructions from the link in my last post to set one.

PingouinDuNord · 2021-12-12 00:27:33

Thanks a lot, it seems to be working.

Now the hostnamectl return the correct hostname and I can start the programs after a reboot.

I still don't understand why the hostname was not set. Looks like an update deleted the previous setting.

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#1 2021-12-11 22:20:05

Error cannot open display: :0.0. Need to kill xfce4-session

#2 2021-12-11 22:33:01

Re: Error cannot open display: :0.0. Need to kill xfce4-session

#3 2021-12-11 22:55:19

Re: Error cannot open display: :0.0. Need to kill xfce4-session

#4 2021-12-11 23:13:01

Re: Error cannot open display: :0.0. Need to kill xfce4-session

#5 2021-12-11 23:15:10

Re: Error cannot open display: :0.0. Need to kill xfce4-session

#6 2021-12-11 23:26:46

Re: Error cannot open display: :0.0. Need to kill xfce4-session

#7 2021-12-12 00:27:33

Re: Error cannot open display: :0.0. Need to kill xfce4-session

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