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I just installed ubuntu 12.04 and wanted to use the gnome 3 shell, according to this site it was just a matter of installing the gnome shell as gnome 3 is already part of ubuntu 12.04

So I did sudo apt-get install gnome-shell and logged out, selected gnome and logged in and I was looking at gnome 2 instead of 3. What went wrong?

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If GNOME 3 thinks your system isn't up to it, it will degrade to a GNOME 2 setup ("fallback mode"). – geekosaur Apr 22 '12 at 11:55
Could you please open a terminal and post the output of gnome-shell --replace? (Open another one and type unity --replace to get Unity back when you're done testing.) – zpletan Apr 22 '12 at 12:13
up vote 2 down vote accepted

gnome-shell requires some level of 3D hardware-acceleration to work.

It doesn't have to be special hardware - integrated graphics should in almost all cases be fine. But 3D acceleration must be working.

Gnome 3's window manager, mutter, is a compositing window manager that is OpenGL accelerated.

If gnome-shell doesn't detect that you have the right capabilities, it'll load into a "fallback mode" which means it loads an old-style panel that looks like Gnome 2 and it doesn't use a compositing window manager.

Ubuntu has helpful ways of installing proprietary drivers for graphics - have you tried these?

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What the OP is seeing is the "old gnome 3". Gnome 3.4 is using llvmpipe to support older hardware.

Here is what gnome-shell now looks like in fallback mode (screenshot is taken with an intel GMA500 using the psb_gfx driver, which is 2d only).


As of my post today, the latest versions of gnome-shell and llvmpipe have not yet been fully ported to Ubuntu or a ppa.

There is a ppa for llvmpipe, but because llvmpipe is under rapid development it is currently better to build it from source (git).

See How to install LLVMpipe?

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I had the same problem. If you're using an ATI Radeon graphics card like me, this might be the solution:

Here's a copy/paste of the important bits:

~$ sudo apt-get purge xorg-driver-fglrx
~$ sudo apt-get install --reinstall libgl1-mesa-glx libgl1-mesa-dri
~$ sudo dpkg-reconfigure xserver-xorg
~$ sudo apt-get install --reinstall xserver-xorg-core
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This thread just saved me thanks! Full story:

Fresh install of Linux Mint 13 (Maya) on a Lenovo Thinkpad T520 with this driver : 01:00.0 VGA compatible controller: NVIDIA Corporation GF119M [Quadro NVS 4200M] (rev a1)

I got gnome-shell with 3D working.

$ sudo apt-get install gnome-shell gnome-session gnome-tweak-tool

I switch to nvidia (I am a sucker for pain) : [][1]

This works great for my external monitor but totally hoses my laptop display. For maybe the wrong reasons I decide to revert to revert to nouveau

$ sudo apt-get purge nvidia*
$ sudo apt-get install xserver-xorg-video-nouveau xserver-xorg-video-all
$ sudo rm /etc/modprobe.d/nvidia-installer-disable-nouveau.conf

This leaves me without openGL so gnome goes into 2D fallback mode. I verify this by running the gnome-shell --replace:

$ gnome-shell --replace
Xlib:  extension "GLX" missing on display ":0.0".

Following the steps to reinstall / reconfigure glx from above:

$ sudo apt-get install --reinstall libgl1-mesa-glx libgl1-mesa-dri
$ sudo dpkg-reconfigure xserver-xorg
$ sudo apt-get install --reinstall xserver-xorg-core
$ sudo reboot

And I was back in business!

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