Comment 12 for bug 573101

It seems that this bug is fixed in Maveric, at least for 173 drivers (173.14.27). I tested 173 and user switching works fine now. According to the changelog the fix is also applied to 96.

There is no problem with installing 173.14.27 on Lucid:

1. download the packages by hand:
    http://mirrors.kernel.org/ubuntu/pool/restricted/n/nvidia-graphics-drivers-173/nvidia-173-kernel-source_173.14.27-0ubuntu1_i386.deb
    http://mirrors.kernel.org/ubuntu/pool/restricted/n/nvidia-graphics-drivers-173/nvidia-173_173.14.27-0ubuntu1_i386.deb
    http://mirrors.kernel.org/ubuntu/pool/main/n/nvidia-graphics-drivers-173/nvidia-173-modaliases_173.14.27-0ubuntu1_i386.deb
    to /tmp

2. cd /tmp

3. dpkg -i nvidia*deb

and voila.

I think that it should be backported to lucid ASAP.