Just a heads up for others who might have this problem -
after an apt-get upgrade, the nvidia glx failed to load after a restart of X, and as a result, steam and games slowed to a crawl, glxgears wouldn't run at all.
After a bunch of searching, this thread had the reason: they changed the X search path in 1.20, so it can't find the nvidia GLX module.
https://bugs.debian.org/cgi-bin/bugr...cgi?bug=900248
The thread recommends modifying /etc/nvidia/current/nvidia-drm-outputclass.conf to point to the nvidia module, which seems to fix it usually.
I needed to do an extra step: on my system, I had an xorg.conf that called module "glx". The fix referred to above didn't work until I removed/renamed the xorg.conf file so that it's not read by X. I didn't know that X doesn't need an xorg.conf anymore, but it seems to run fine without it now.
Hope this helps somebody having the same problem.
