How to resolve the "/lib/modules/3.13.0-27-generic/build: No such file or directory" error message?
you need to install linux-headers-3.13.0-27-generic package
sudo apt-get install linux-headers-3.13.0-27-generic
or better
sudo apt-get install linux-headers-`uname -r`
this will provide the link /lib/modules/3.13.0-27-generic/build
I was using a kernel (v3.13) that is not meant to be used with the distro version I'm using (Ubuntu 14.10).
So I installed the latest possible kernel for my distro by running the following command:
sudo apt-get install linux-generic
It fixed my brightness issue too !