As you said in your own answer you can add the testing ppa.
The second way is to simply remove xserver-xorg-legacy and use the stable ppa:
First remove the xserver-xorg-legacy without touching depending packages:
sudo dpkg -r --force-depends xserver-xorg-legacy
Allright - Bumblebee is working again. But apt will give you errors because of missing dependencies.
This can be fixed by creating a dummy-package for xserver-xorg-legacy using equivs.
First we create a config file using equivs-control:
This will create the config file for the new package in the current directory.
You can use nano to edit this one:
The content of the file should look like this:
### Commented entries have reasonable defaults.
### Uncomment to edit them.
# Source: <source package name; defaults to package name>
# Homepage: <enter URL here; no default>
# Maintainer: Your Name <email@example.com>
# Pre-Depends: <comma-separated list of packages>
# Depends: <comma-separated list of packages>
# Recommends: <comma-separated list of packages>
# Suggests: <comma-separated list of packages>
# Provides: <comma-separated list of packages>
# Replaces: <comma-separated list of packages>
# Architecture: all
# Multi-Arch: <one of: foreign|same|allowed>
# Copyright: <copyright file; defaults to GPL2>
# Changelog: <changelog file; defaults to a generic changelog>
# Readme: <README.Debian file; defaults to a generic one>
# Extra-Files: <comma-separated list of additional files for the doc directory>
# Files: <pair of space-separated paths; First is file to include, second is destination>
# <more pairs, if there's more than one file to include. Notice the starting space>
Description: Dummy package for nvidia-375.66 update
This Package does nothing... it just exists...
Important at this point is the Package name:
And that you have to stage the version
If you're done with your config you have to create the package from your config:
This will create a package file with the given name and the version.
In my case this was xserver-xorg-legacy_1.18.4-1ubuntu0.2_all.deb
Okay, let's install it using dpkg:
sudo dpkg -i xserver-xorg-legacy_1.18.4-1ubuntu0.2_all.deb
xserver-xorg-legacy doesn't do something anymore and apt is happy with no missing dependencies.
Good Luck ;-)