Failed to open connection to "session" message bus: Unable to autolaunch a dbus-daemon without a $DISPLAY for X11

[jiye]

I have a 4.19 linux ubuntu distro running on my LS1021-TWR evaluation kit and I am trying to make the dbus works on the device.

I really do not think this is dependent on what boards I am using 

However, I have encountered the following error which I could not figure out:

Failed to open connection to "session" message bus: Unable to autolaunch a dbus-daemon without a $DISPLAY for X11

I found something that says about this issue but I still do not have any clues about the cause.

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=690530

Hope someone can help.

[b36401 · Accepted solution]

Such error message means that you need to assign a display to the application.
I mean you need to perform something like "export DISPLAY=:0" prior to running it.

[jiye]

I fixed it by performed the following commands on the command line:

(1)DISPLAY=":0" DBUS_SESSION_BUS_ADDRESS="unix:path=/run/dbus/system_bus_socket"

(2)export DBUS_SESSION_BUS_ADDRESS

but later on:

when I ran dbus on this device I always encountered this error below: any one knows why?

$2 = (gchar *) 0xb2c05668 "GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.byos.server was not provided by any .service files"

this is the debug statement from the gdb