TWZ » Troubleshooting


Cannot open display

When it try to start a graphical application from a terminal and it fails returning only an error of type cannot open display[0] is very likely to be an environment variable error. In Unix-like systems for each Xorg server must be a logical display identifier of the form :0, :1, ..., :0.0, :0.1, ..., :1.0, :1.1 and so forth.

Messages like:

** (PROGRAM_NAME:PORT): CRITICAL **: Failed to parse arguments: Cannot open display:[1]
the most frequent:
(PROGRAM_NAME:PORT): Gtk-WARNING **: cannot open display: VALUE
or even
Error: cannot open display: VALUE

indicate that the VALUE logical display cannot be accessed ...

No protocol specified

In Unix-like systems, if it fails to start any graphical application from a terminal which returns an error message contains the following statement:

No protocol specified

with the consequent final warning (that in these cases, must not be considered because there's the first priority statement[0]) of the kind shown below:

WARNING: cannot open display: :x.x

or in rare cases, an Xlib[1] error such as:

Xlib: connection to "<hostname>:x.x" refused by server
Xlib: No protocol specified

RTNETLINK answers: File exists

When the virtual terminal displays the following message:

RTNETLINK answers: File exists

It should not be interpreted literally.

It's a misuse of (rt)netlink interface for communication with the kernel. Generally the message is caused by the Dynamic Host Configuration Protocol (DHCP) system which assigns an "X" IP address to the computer on which it was previously set same "X" IP address.

None of the authentication protocols specified are supported

In Unix-like systems, if you try to start a graphical application as no "session manager" executor root/user in pseudo-terminal and it returns the following output:
Failed to connect to the session manager: None of the authentication protocols specified are supported
or
Warning: Tried to connect to session manager, None of the authentication protocols specified are supported

It may be required a login shell ...

NVidia Driver and ignoreABI Option

If after upgrading xorg 1:7.6+8 (Debian) or xorg-x11-server 1.7.99.3 (Fedora)

nvidia driver don't work, X don't start

and you have found in the following files:

/var/log/gdm3/\:0.log*
or /var/log/Xorg.*.log*: