Bug#984826: tigervnc-standalone-server: Unable to init server: Could not connect: Connection refused

[Matthias Klein]

Package: tigervnc-standalone-server
Version: 1.11.0+dfsg-1
Severity: important

Dear Maintainer,

since the update to version 1.11 the vncserver does not start anymore. Until prior to the update, the server worked with MATE.

My ~/.xstartup file contains the following:
unset SESSION_MANAGER
unset DBUS_SESSION_BUS_ADDRESS
exec /usr/bin/mate-session &
#lxterminal & /usr/bin/lxsession -s LXDE &

Since the update "vncserver --localhost no" terminates with the following message:

Xvnc TigerVNC 1.11.0 - built 2021-02-22 17:19
Copyright (C) 1999-2020 TigerVNC Team and many others (see README.rst)
See https://www.tigervnc.org for information on TigerVNC.
Underlying X server release 12010000, The X.Org Foundation


Mon Mar 8 20:00:18 2021
vncext: VNC extension running!
vncext: Listening for VNC connections on all interface(s), port 5901
vncext: created VNC server for screen 0
3NI3X0 New Xtigervnc server 'WS-MAK:1 (mak)' on port 5901 for display :1.
3NI3X0 Use xtigervncviewer -SecurityTypes VncAuth,TLSVnc -passwd /home/mak/.vnc/passwd WS-MAK:1 to connect to the VNC server.
ComparingUpdateTracker: 0 pixels in / 0 pixels out
ComparingUpdateTracker: (1:-nan ratio)
Unable to init server: Could not connect: Connection refused

** (mate-session:11791): WARNING **: 20:00:18.826: Cannot open display:


I also tried to use LXDE as a test. Also there the vncserver does not start anymore.

Xvnc TigerVNC 1.11.0 - built 2021-02-22 17:19
Copyright (C) 1999-2020 TigerVNC Team and many others (see README.rst)
See https://www.tigervnc.org for information on TigerVNC.
Underlying X server release 12010000, The X.Org Foundation


Mon Mar 8 19:55:15 2021
vncext: VNC extension running!
vncext: Listening for VNC connections on all interface(s), port 5901
vncext: created VNC server for screen 0
3NI3X0 New Xtigervnc server 'WS-MAK:1 (mak)' on port 5901 for display :1.
3NI3X0 Use xtigervncviewer -SecurityTypes VncAuth,TLSVnc -passwd /home/mak/.vnc/passwd WS-MAK:1 to connect to the VNC server.
ComparingUpdateTracker: 0 pixels in / 0 pixels out
ComparingUpdateTracker: (1:-nan ratio)
** Message: 19:55:15.571: main.vala:101: Session is LXDE
** Message: 19:55:15.571: main.vala:102: DE is (null)
** Message: 19:55:15.571: main.vala:112: No desktop environnement set, fallback to LXDE

(lxsession:10182): Gtk-WARNING **: 19:55:15.572: cannot open display: :1
Unable to init server: Could not connect: Connection refused

(lxterminal:10181): Gtk-WARNING **: 19:55:15.638: cannot open display: :1


When I downgrade with the packages tigervnc-standalone-server_1.10.1+dfsg-9_amd64.deb and tigervnc-common_1.10.1+dfsg-9_amd64.deb the vncserver works again.

Best regards,
Matthias

-- System Information:
Debian Release: bullseye/sid
APT prefers testing
APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 5.10.0-3-amd64 (SMP w/8 CPU threads)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/bash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages tigervnc-standalone-server depends on:
ii libaudit1 1:3.0-2
ii libbsd0 0.11.3-1
ii libc6 2.31-9
ii libfile-readbackwards-perl 1.05-2
ii libgcrypt20 1.8.7-3
ii libgl1 1.3.2-1
ii libgnutls30 3.7.0-7
ii libjpeg62-turbo 1:2.0.6-2
ii libpam0g 1.4.0-4
ii libpixman-1-0 0.40.0-1
ii libselinux1 3.1-3
ii libstdc++6 10.2.1-6
ii libsystemd0 247.3-1
ii libunwind8 1.3.2-2
ii libxau6 1:1.0.9-1
ii libxdmcp6 1:1.1.2-3
ii libxfont2 1:2.0.4-1
ii perl 5.32.1-3
ii tigervnc-common 1.11.0+dfsg-1
ii x11-xkb-utils 7.7+5
ii xauth 1:1.1-1
ii xkb-data 2.29-2
ii zlib1g 1:1.2.11.dfsg-2

Versions of packages tigervnc-standalone-server recommends:
ii libgl1-mesa-dri 20.3.4-1
ii x11-xserver-utils 7.7+8
ii xfonts-base 1:1.0.5

Versions of packages tigervnc-standalone-server suggests:
ii xfonts-100dpi 1:1.0.4+nmu1.1
ii xfonts-75dpi 1:1.0.4+nmu1.1
ii xfonts-scalable 1:1.0.3-1.2

-- Configuration Files:
/etc/tigervnc/vncserver.users changed [not included]

-- no debconf information

[Matthias Klein]

Am Mon, 8 Mar 2021 22:44:37 +0100
schrieb Joachim Falk <joachi...@gmx.de>:

> Hi Matthias,
>
> I tried to replicate the problem, but could start the mate desktop
> just fine. I will attache my configuration. I used

Hi Joachim,

Thanks a lot for your help!

> Can you try to start something simpler to determine where exactly the
> problem is? Use something like: tigervncserver --localhost no
> --xstartup /usr/bin/xterm This should get you a VNC session running a
> simple xterm.

The call tigervncserver --localhost no --xstartup /usr/bin/xterm
started an xterm and the MATE desktop in the background.

After that I tried some variants in the ~/xstartup file. I got the
original content from the internet, and didn't really understand it.

The following variant works:
unset SESSION_MANAGER
unset DBUS_SESSION_BUS_ADDRESS
/usr/bin/mate-session

That means instead of "exec /usr/bin/mate-session &" I now use
"/usr/bin/mate-session" in the last line.

Do you have any idea why the original call doesn't work anymore, and
what is the difference between the calls?

Many greetings,
Matthias

[Joachim Falk]

In 1.11, autokill is enabled on default. If autokill is enabled, then the Xtigervnc server is killed when the xstartup script terminates. If you use "/usr/bin/mate-session &", then the xstartup script will immediately terminates because the mate desktop is started in the background, that is what the & does. Removing the & will start the mate desktop in the foreground, which means the xstartup script will only terminate after you have logged out of the desktop.
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