Wayne D's Blog

Before installing CUDA 7.5 on Centos 7 you need to update both your kernel and X using yum update otherwise mayhem will ensue and X won't start. I installed them in the wrong order and ended up with the following error when I tried to start X.

[ 467.272] (EE) NVIDIA(0): Failed to initialize the GLX module; please check in your X
[ 467.272] (EE) NVIDIA(0): log file that the GLX module has been loaded in your X
[ 467.272] (EE) NVIDIA(0): server, and that the module is the NVIDIA GLX module. If
[ 467.272] (EE) NVIDIA(0): you continue to encounter problems, Please try
[ 467.272] (EE) NVIDIA(0): reinstalling the NVIDIA driver.

reinstalling the nvidia drivers didn't solve the problem the key turned out to be this which occurs a bit higher in the Xorg.0.log file

[ 467.240] (II) LoadModule: "glx"
[ 467.240] (II) Loading /usr/lib64/xorg/modules/extensions/libglx.so
[ 467.261] (II) Module glx: vendor="X.Org Foundation"
[ 467.261] compiled for 1.17.2, module version = 1.0.0
[ 467.261] ABI class: X.Org Server Extension, version 9.0
[ 467.261] (==) AIGLX enabled

That's not the glx driver that NVIDIA needs so I went to /usr/lib64/xorg/modules/extensions and removed the libglx.so that was there and made a link to the NVIDIA version.

cd /usr/lib64/xorg/modules/extensions/
rm libglx.so
ln -s /usr/lib64/nvidia/xorg/libglx.so

not pretty but it worked.