Restore a package to original version

[jamesharper-caesar]

Hi, I've been been having some problems with my touchpad since a dist-upgrade I did a few days ago. The touchpad works but runs off the mouse settings and had lost many of its features such as vertical scroll and emulated middle click.

I think the problem is the new version of xserver-xorg-input-synaptics installed with the dist-upgrade so I was wondering how to restore xserver-xorg-input-synaptics to the version when I first installed Ubuntu on my laptop. I'm running 12.04.

Thank you in advance for any help!

[ian-weisser]

You can downgrade a package using the dpkg command, but it's not a supported nor tested action.

This is the actual warning on the subject from the dpkg man page:

Warning: At present dpkg does not do any dependency checking on
downgrades and therefore will not warn you if the downgrade
breaks the dependency of some other package. This can have seri‐
ous side effects, downgrading essential system components can
even make your whole system unusable. Use with care.

How you do it:
1) Backup your data
2) Create an install media in case this destroys your system.
3) Download the original deb package (version 1.5.99.902-0ubuntu5) from http://packages.ubuntu.com.
4) Put the package in your /var/cache/apt/archive/
5) Use the command sudo dpkg --force-downgrade xserver-xorg-input-synaptics
I have never used force-downgrade, so the syntax may be slightly off.

If downgrading does break your system or cause data loss, there is not much we can do beyond advising a reinstall.