Comment 11 for bug 982485

There seems to be 2 different situations in current reports and latest posts at forums:

1) Very slow GL performance. Unity 3D session varies from barely usable (more powerful VGA cards) to unusable session (low-end card - session simply stalls). No crash of Compiz / Unity Plugin. The Unity 2D session is normal. Unity --reset, or creating a new user with default settings and logging in, doesn't fix the problem.

2) Compiz simply crashes when Unity (3D) session is loaded, right after a succesful login in lightdm. The segfault is visible via logs. Since it crashes, there won't be a launcher, global panel, indicator on the desktop (no Compiz == no Unity Plugin loaded). The 2D session works fine.

As a test, have you people tried installing some previous version of NVidia driver? I have tried 295.33 only, and reached the very same results. I will test 295.20 still today as soon as I can.

You can get previous NVidia drivers versions at http://www.nvidia.com/Download/Find.aspx?lang=en-us or via ftp download.nvidia.com.

In order to test / install a previous driver version:
1) Download the driver to a known directory (~/Downloads, for example)
2) Press Ctrl+Alt+F6 to switch to another Virtual Terminal and login with your User/Password
3) Run "sudo service lightdm stop" (or NVidia installer will not run, because there's an active X session)
4) Run "cd ~/Downloads && sudo chmod +x ~/Downloads/NVIDIA-Linux-x86_64-295.33.run" (if that's the version you have downloaded, to make the installer executable)
5) Run "sudo ./NVIDIA-Linux-x86_64-295.33.run" and press "OK" to all installer questions (default options)
6) As the installer finishes, run "sudo reboot now" to reboot the machine.
7) At lightdm, login to Unity 3D and verify if there was any change or improvement.

Also:
- Make sure you are not running nouveau. You can check if nouveau is loaded by running "lsmod | grep -i nouveau". It should display no results.
- Make sure your currently loaded NVidia kernel module is the same version as the installed drivers. You can check that nvidia Kernel module is is loaded with "lsmod | grep -i nv". If you installed NVidia drivers from the proprietary/binary installer from NVidia website/FTP it should output "nvidia". If you have NVidia installed from Ubuntu repos (pakage nvidia-current) it should output nvidiafb. To check the Kernel module version, use "modinfo nvidia" or "modinfo nvidiafb". It should output "version: <version number> along with other module details. This version should match the drivers you installed.

I'm not sure this is NVidia related. If everyone could try previous (known to work) versions of NVidia drivers, it could be very helpful for properly triaging this bug. I recommend testing 295.20 and previous ones.

If anyone needs help with these procedures, start a thread at UbuntuForums in the Ubuntu+1 sub-forum.

Feel free to contact me for any further info.

Regards,
Effenberg