Title: NVIDIA Nouveau Driver: No more 3D acceleration?
Tags: compiz;nvidia;3d;nouveau
Question: After playing around with my drivers, my Nouveau driver no longer seems to support 3D acceleration: Compiz effects are gone, as are 3D gaming capabilities.
Nouveau is still doing something correctly in 2D (e.g. the 1600x900 resolution is still correct, as compared to no NVIDIA driver at all, when it's 1280x768 instead).
How do I fix this without reinstall Ubuntu for the billionth time?
xorg.conf's that I've tried:
(empty)
This (which was the original):
Section "Device"
Identifier      "Default Device"
Driver  "nouveau"
EndSection
Other things I've tried:
modprobe nouveau
sudo apt-get purge xserver-xorg-video-nouveau --remove
sudo apt-get install xserver-xorg-video-nouveau --reinstall
Uninstalling/reinstalling through Additional Drivers
Comment: @htorque: 1. Done. 2. `lrwxrwxrwx 1 root root 24 2011-08-01 23:52 /etc/alternatives/gl_conf -> /usr/lib/mesa/ld.so.conf`. 3. No, I've removed that when uninstalling the proprietary driver. (nouveau **does start**, it's just that I don't get 3D acceleration anymore, just 2D graphics). 4. Yes, there are 5 entries that match `nouveau`. 5. No. 6. No. This thing was fine like 20 minutes before I fiddled around with the drivers, I didn't add/remove anything else during that time :)

Comment: 1. Remove the xorg.conf file. 2. Please add the output of `ls -al /etc/alternatives/gl_conf`. 3. Do you have a file called `nvidia-installer-disable-nouveau.conf` (or similar) in `/etc/modprobe.d`? 4. Are nvidia or nouveau in the output of`lsmod` after a boot?

Comment: 5. Did you recently update the system (like Xorg related packages)?6. Are you using any Xorg PPAs by any chance?

Here is the accepted answer: Fixed...
(But I'm not sure why!)
I followed these instructions to reinstall the drivers, and rebooted.
Nothing changed.
Then I went into Additional Drivers and enabled Nouveau (which I'd already enabled and disabled numerous times, and which should have been enabled here)... and then I got 3D after I rebooted.


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