Salvatore Iovene

Using Debian Test­ing or Unsta­ble, or a fre­quently upgraded ver­sion of Ubuntu, when doing an apt-get update && apt-get upgrade often will install a slightly newer ver­sion of xserver-xorg-code, and this will break the NVIDIA pro­pri­etary dri­vers, if you, like me, pre­fer to install them using the offi­cial NVIDIA installer. When this hap­pens, at your next reboot, or next time you start X, this will crash.

Fol­low this instruc­tions and you won’t need to rein­stall the NVIDIA dri­ver from scratch each time. First of all, stop your login man­ager (gdm assumed here):

/etc/init.d/gdm stop

Then move to:

cd /usr/lib/xorg/modules/extensions

Nor­mally it should look like this:

total 956K
1 root root  19K 2007-01-09 21:13 libdbe.so
1 root root  34K 2007-01-09 21:13 libdri.so
1 root root 145K 2007-01-09 21:13 libextmod.so
1 root root   18 2007-01-15 20:42 libglx.so->libglx.so.1.0.9742
1 root root 676K 2007-01-15 20:42 libglx.so.1.0.9742
1 root root  28K 2007-01-09 21:13 librecord.so
1 root root  38K 2007-01-09 21:13 libxtrap.so

Notice the sym­bolic link from libglx.so to libglx.so.1.0.9742. In your case, instead, the instal­la­tion of a newer xserver-xorg-core over­wrote the libglx.so with the nor­mal one pro­vided by the X Server. What you have to do is sim­ply restore the pre­vi­ous sit­u­a­tion. Remove the libglx.so file:

sudo rm libglx.so

And make the sym­bolic link again:

sudo ln -s libglx.so.1.0.9746 libglx.so

Of course the ver­sion num­ber, in my case 1.0.9746 may be dif­fer­ent in your case. Now you can sim­ply start the gdm login man­ager again:

sudo /etc/init.d/gdm start

Every­thing should be work­ing again.

Thanks to http://osrevolution.wordpress.com/ for this.