I am about to install a patch for wireless drivers named Compat Wireless in order to solve a problem with my WiFi channel (it locks on the not existing -1 channel) on my Ubuntu Linux v12.04 and Kali Linux v1.0.9.  But first I would like to know if this patch is already installed (why installing something I do have?).I have done some research about, and I can not find a way to know if my patch is already there, nor a generic method to list installed patches. I don't even know if it is possible or not to obtain such info from a running Linux.Any ideas, please?
How can I check if a certain patch is already installed in my system?
kernel;patch
Linux is NOT Windows and thus patches are actually totally re-compiled/re-loaded from the base code after source code modifications and distributed as a package.  Thus it is a bit difficult to know if some specific change has been incorporated into a binary without downloading the source and checking for the specific source code change.Versions do not always help either.  For example RedHat backports source code changes to older but supported versions of and application and re-released the package changing only the build number but not the version.  So in RedHat, you cannot be totally sure if a change that was made by the developer releasing a new sub-version has not been backported to one of their re-released modules.  This type of stuff drives me nuts.Final though, remember there are multiple distributions of Linux with differing methods of package management, versioning and support.  Summary, to be absolutely sure a source code change has been implemented, you have to go to the source of the specific package for the specific distribution you are using.