what is dbus daemon and why vlc needs it

Question

I have cross-compiled VLC (version 2.1.2) media player using buildroot for an arm board. I have connected the board to my linux PC using serial cable. When I try to run the player using "vlc" command in minicom, which is located in /usr/bin of my root filesystem. I get the following error:

inhibit interface error: Failed to connect to the D-Bus session daemon: /usr/bin/dbus-launch terminated abnormally with the following error: Autolaunch error: X11 initialization failed.

Can anyone please clarify what this error means and also can any one please tell me what is a dbus and why it is required for my VLC player.

Thanks for any help.

Misapply

The internet is a great place to gather basic information about a wide range of topics, such as "What is dbus?". (Anyway, how is this VLC supposed to play without X11 being "initialized correctly"?) – Upu

Thanks for quick reply. Can you please suggest how to initialize X11. I am a newbie to linux. – Misapply

X11 is usually used for the "desktop". Is such available in your installation? – Upu

Yes libX11 is present in my rootfs/usr/lib directory. – Misapply

But is X11 running? Look for a process called /usr/bin/X. Which desktop do you use? KDE? Gnome? Unity? Which Linux distribution? – Geometry

It looks like you are using an embedded ARM board, such as a Beaglebone or a RaspberryPi... Those don't have the usual desktop, but many still can handle the X server. You can try running startx to start your X11 server. If that fails do just X as root and see what happens. – Pamphleteer

@Pamphleteer BR has at least FluxBox and Enlightenment. Try FluxBox and select xdm. That should start X automatically on startup. – Illomened

Answer 1

I am working on a minimal rootfs based on buildroot. This error is solved for me after I have included the package "twm" in my rootfs. Then after the board is up I run following commands on the terminal:

export DISPLAY=:0
startx &

then run vlc

vlc

This way I got rid of this error.

Misapply

Answer 2

Since you say that you have cross compiled vlc and facing dbus launch issues, I expect you are working on a minimal root fs.

Try doing this in your terminal before you run vlc:

$ export DISPLAY=:0

If you have compiled dbus with x11 support, then dbus-launch will succeed.

Rattlehead

Apparently, this is also needed in a script called from a cron job. (Raspbian on a 3B+, fully updated just before testing on Feb. 2, 2020) – Debbydebee