The "OpenGL/GLX Information" tab of nvidia-settings only displays "Fail to query the GLX server vendor.". This is caused by missing x11-apps/mesa-progs, because it no longer gets pulled in by media-libs/mesa-7.3-r1. Possible solution: either have mesa or nvidia-settings pull in mesa-progs.
I'm seeing this problem also, but I do have mesa + mesa-progs both installed: x11-apps/mesa-progs-7.4 media-libs/mesa-7.4 x11-drivers/nvidia-drivers-180.44 media-video/nvidia-settings-180.44 xorg-server-1.5.3-r5 Also, probably related, when I try running glxinfo, glxgears, or any gl games (e.g. games-fps/nexuiz), I get strange RGB messages and they fail to start, with no output besides: Couldn't find RBG GLX visual or fbconfig. My xorg log says: (II) Initializing extension GLX I've rebuilt most of X, mesa, mesa-progs, nvidia, nvidia-settings with no luck.
$ glxinfo | grep direct
Oops, didn't read carefully enough. If glxinfo doesn't work, check: $ eselect opengl list
This issue resolved itself for me after removing mesa, mesa-progs, nvidia-drivers and all of xorg, then rbeuilding them all. While it was happening, opengl was set to nvidia. any glx command failed. Running revdep-rebuild didn't help, neither did just rebuilding mesa, xorg-server, or nvidia-drivers/nvidia-settings.
Hmm, strange, but can't really do anything w/o a way to reproduce it. Reopen if you it happens again.