Comment 7 for bug 189844

> Is there any benefit or problem by just using one tiny file from Feisty
> to fix this rather than swapping out the entire xserver package?

One benefit is that it is simple and easy to do.

Possible problems:
  1. The older driver version might contain ugly bugs that aren't present in the newer version. However, you already know that the newer driver has at least one ugly bug that the older driver doesn't, so this is pretty much a moot point.
  2. In general, binaries compiled with different compilers could have ABI (application binary interface) mismatch problems, but Feisty and Gutsy use the same version of gcc so that's not going to be a problem in this case.
  3. You might notice problems if a driver binary is linked against an older, incompatible library or if the driver API has changed. However, since you don't get any unresolved symbol errors and the X driver API probably doesn't change very rapidly, you're almost certainly OK.
  4. Your fix isn't managed by apt. This is probably the biggest problem. If a new version of the driver comes out, running 'sudo apt-get upgrade' will probably overwrite your nv_drv.so and force you to copy it over again.

Downgrading the driver package should take care of problems 2 through 4. You shouldn't need to downgrade all of X. Building an older xserver-xorg-video-nv package for Gutsy is easy if you use prevu:

   $ sudo apt-get install prevu
   $ sudo prevu-init # answer yes when it asks if you want your /etc/apt/sources.list updated
   $ prevu http://archive.ubuntu.com/ubuntu/pool/main/x/xserver-xorg-video-nv/xserver-xorg-video-nv_2.0.0-0ubuntu3.dsc

Once the package is done building, fire up synaptic, reload the package information, find xserver-xorg-video-nv, go to Package->Force Version, select the older version, and install it. You may also need to go to Package->Lock Version after downgrading, but I'm not sure since I've never forced an older version of a package.

I found the above URL by going to <http://packages.ubuntu.com/>, searching for xserver-xorg-video-nv for Feisty, and copying the link to the .dsc file under the "Download Source Package" section in the right-hand side of the package details page.

Hope this helps!