TigerVNC problems

[mboehmer]

Dear community,

 

unfortunately, "armbianmonitor -u" doesn't give me a link anymore, and I'm not sure if uploading works at all. So I cant provide the information

 

As our deployment date approaches, we try to finalize our Armbian system for North Pacific seafloor... and found some unexpected problems (problems seem alwas to be unexpected):

The TigerVNC has two problems on Armbian, and it would be great if you could verify that issues and maybe problem some helpful ideas:

 

(1) TigerVNC (tigervnc-common/stable,now 1.9.0) needs the following workaround to start at all:

LD_PRELOAD=/lib/aarch64-linux-gnu/libgcc_s.so.1 vncserver :1 -localhost no

   Seems to be libunwind8 related, and is ugly, but not the main problem.

 

(2) TigerVNC can be started by crontab "@reboot", but fails to open a desktop. There are messages about dbus problems, the display closes afterwards.

 

I use Armbian NEXT, with Debian Buster, and kernel is locked to 4.19.90 (due to the various troubles with the new kernel, which seems to be optimzed for video playback but not stable operation).

 

Any help is appreciated, and if you need more information, please let me know.

 

So far, Michael

 

 

[linuxfan]

Thanks, you helped me with the first part of fixing TigerVNC on current Armbian, hopefully I can help you with the second one:

# apt install dbus-x11

 

This package contains the program "dbus-launch".

For example the desktop environment Xfce, at least in our use case, tries to launch "dbus-launch", but won't find it. It seems the path environmental variables are not set when you launch something from within /etc/crontab. I load them with the "source" command (also available as ".") from /etc/profile. This could fix other possible bugs, too:

 

/etc/crontab

@reboot username . /etc/profile LD_PRELOAD=/lib/aarch64-linux-gnu/libgcc_s.so.1 tigervncserver -localhost no

[mboehmer]

Thanks for the information.

At the moment, I'm happy with the rc.local solution, as it works

I was in contact with Adrian Bunk, who is maintaining libunwind (and was at university with me), but didn't get any response so far.

 

I will try the crontab solution as time permits, due to Corona we are delayed with deployment, and things might shift for at least six months

[mboehmer]

Hi Linuxfan,

 

your line doesn't work for me. We use ZSH on the system, and executing the /etc/profile gives us a working VNC server, but no ZSH anymore. Which in turn leads to malfunctioning of the startup of hardware... if you can give me a hint on how to source the correct environment, it would be great.

 

See you, Michael

[mboehmer]

Solved, finally. A collegue of mine (ZSH fan :) made it working.

Basically, the dbus_x11 was first part of problem, and the missing ZSH entry in the user crontab:

 

SHELL=/usr/bin/zsh

@reboot /usr/bin/zsh -l -c "LD_PRELOAD=/lib/aarch64-linux-gnu/libgcc_s.so.1 vncserver -localhost no"

 

Now we are just "stuck" with the libunwind problem, but that can be worked around by PRELOAD for now.

Somehow I'M a bit happy about the forced lockdown now, as it shifted deployment and allows us to solve some problems in a really good manner, and not under high time pressure :)

[linuxfan]

Some recent Armbian update did something to libunwind and so destroyed my crontab setup. I removed the whole preload part and now VNC works again. It also works with bash using /usr/bin/bash -l -c 'vncserver -localhost no'

[RussianNeuroMancer]

This issue is fixed since version 1.10.1+dfsg-4 and Ubuntu 20.10 already ship newer package (1.10.1+dfsg-7).

You can use TigerVNC 1.10.1+dfsg-7 on Ubuntu 20.04 as well, but this will require manual downloading of tigervnc packages here: https://launchpad.net/ubuntu/+source/tigervnc

 

Relevant bugreports:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=932499

https://github.com/TigerVNC/tigervnc/issues/1023