"Unable to open a connection to X. Check your DISPLAY environment variable and make sure that you have enabled X. If you are running remotely, make sure that you have a remote connection which will allow an X connection.
Just a wild guess:
There was an update to xorg-x11-server recently, this will break the nvidia driver if you installed it “the hard way” (by downloading and running the .run file from the nvidia homepage).
If that’s how you installed it, you have to re-install it after any update to Mesa-libGL1 and xorg-x11-server, as the nvidia driver replaces parts of those with its own versions.
Maybe this causes your issue?
Try re-installing the driver.
To check whether the driver is working, install “Mesa-demo-x” and run:
I have been running into this issue as well. After many years of trouble shooting i think i might have and idea why it isn’t working for me and why none of the resolutions on this post work with the exception of xhost +; steam.
First thin first is when i open steam on some of my machines, in the most recent case a Thinkpad T400, I get the error where steam cannot open a connection to X. Everything else works fine and running
. GLXgears works as do a few other programs from the Games and Packman repository.
So it just dawned on me… Xhost… Xhost might have some tie to the localhost. Next story
On most of my Linux installs i change the hostname to something i can remember, usually something cheeky like “pornbox” or something else i can remember easly when SSHing into the machine or doing VNC. Now on Suse based installs i usually change the hostname via Yast>Network . Sadly it dawned on me i usually do this AFTER i set up steam.
Hence my hypothesis that Steam is looking for the Xhost on the local host using the default random one the suse installer chooses automatically like “linux_1723gsaeywv”. Since that got changed Steam cannot find the display because the localhost as it knows it cannot be found.
Installing and reinstalling steam doesn’t function in fixing this. and in the case of one machine (thinkpad T400) if i do the xhost+; steam i get the now notorious line 713 error. On my Poweredge with nvidia as well as some other thinkpads and various machines once i did the xhost +; steam , everything worked fine and normally after a reboot.
Could it be that the YAST>NETWORK changes the hostname in /etc/hostname but doesnt add it to /etc/hosts?
Will need to experiment with this some more before posting a bug report, if there is one.
=_=# Well that didnt work. My hypothesis might be wrong. Added the line in /etc/hosts as follows using that cheeky example made in the previous post.
127.x.x.x localhost 127.x.x.x pornbox
Now after a reboot or two and letting some programs like dolphin acclimate to the changes, steam still cannot find a connection to X on my Thinkpad T400. Back to 1² (square one for you non-math humored people ~_0).