after kernel upgrade the nvidia binary drivers stop working correctly

[JThoennes]

This issue happened the second time to me:

A regular update required a reboot since kernel components where changed.
After the reboot the X11 display comes up without the second monitor and
only the upper half of the screen is displayed (screen seems to be double as tall
as the usual screen, looks like stretched).

Switching to the console view, this issue can be solved by installing the needed
kernel headers:

aptitude install linux-generic

installs linux-headers-generic (= 3.13.0.49.56)

Now both (!!) NVIDIA driver module packages can be recompiled / relinked:

dpkg-reconfigure nvidia-331
dpkg-reconfigure nvidia-331-uvm

After reboot the X11 displays works as expected in a dual-screen setup on
two monitors side-by-side.

To me this looks like a dependency issue with drastic consequences: critical,
but probably easy to solve.

# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 14.04.2 LTS
Release: 14.04
Codename: trusty

# dpkg -l |grep nvidia
ii nvidia-331 331.113-0ubuntu0.0.4 amd64 NVIDIA binary driver - version 331.113
ii nvidia-331-uvm 331.113-0ubuntu0.0.4 amd64 NVIDIA Unified Memory kernel module
ii nvidia-libopencl1-331 331.113-0ubuntu0.0.4 amd64 NVIDIA OpenCL Driver and ICD Loader library
ii nvidia-opencl-icd-331 331.113-0ubuntu0.0.4 amd64 NVIDIA OpenCL ICD
ii nvidia-prime 0.6.2 amd64 Tools to enable NVIDIA's Prime
ii nvidia-settings 331.20-0ubuntu8 amd64 Tool for configuring the NVIDIA graphics driver

# dpkg -s linux-generic
Package: linux-generic
Status: install ok installed
Priority: optional
Section: kernel
Installed-Size: 29
Maintainer: Ubuntu Kernel Team <email address hidden>
Architecture: amd64
Source: linux-meta
Version: 3.13.0.49.56
Depends: linux-image-generic (= 3.13.0.49.56), linux-headers-generic (= 3.13.0.49.56)
Description: Complete Generic Linux kernel and headers
 This package will always depend on the latest complete generic Linux kernel
 and headers.