Apply fix to drivers

Question

Hi everyone,
I hope I'm not in the wrong place for this and I hope this is not to nooby for this forum.
Anyway my problem:
The pressure of my Lenovo Thinkpad Yoga (Laptop/Tablet) is doing weired stuff.
The harder I press, the thicker the line gets... so far so good but(!) at some point the thickness jumps back to minimum and then increases again.
My research has led up to this: http://www.spinics.net/lists/linux-input/msg29435.html
Summary: The yoga has 1024 pressure levels but the driver only supports 512 wich leads to the described behaviour.
Now the part where I kindof feel a little nooby.
The site behind the link contains a patch and now I'm lost... I don't really know what to apply the patch to / where to get the sources.
I guess I could figure the rest out if you guys could help me find the packages/sources I need to apply the patch to. Of course I would post a summary of (hopefully) my success here once I am done.
I have some experience in building packages and my research has shown that I "only" need to run "patch [file]" whereas the [file] should contain the patch from the website.
The thing I am sadly not so familiar with is the way linux does drivers. From what I have gathered I think drivers are (always?) part of the kernel or at least kernelmodules.
Thanks a lot in advance!
Last edited by Ch33f (2014-08-26 17:19:31)

Answer 1

It is possible to build your own kernel, or to rebuild the existing kernel and install that patch.  Conceptually, to do that you will want to get the kernel sources and find drivers/input/tablet/wacom_wac.c b/drivers/input/tablet/wacom_wac.c and apply those changes with the patch command.  Then make and install the kernel and/or just the module.  Easy.
The devil is in the details.   Depending on your skills, you might start by making a request in 'AUR Issues, Discussion, and PKGBUILD Requests" and see what happens.   Alternately, you could grab the package to make our kernel from the ABS, and add the patch to the package and build and install the modified 'linux' package. 
The quick and nasty way I would do it would be to grab the kernel sources from kernel.org, unpack it to a directory in your home,  Grab your running kernel configuration from /proc/config.gz, unpack it, and put that in with the kernel source, patch drivers/input/tablet/wacom_wac.c b/drivers/input/tablet/wacom_wac.c, compile the kernel, find the module, and manually copy it to the appropriate place under /lib/modules.   
If you are interested in trying to compile the kernel (it really is not that bad), check our wiki, and also check the Gentoo Handbook on how to build a kernel.  The Gentoo documentation is excellent in this regard.  If you are not interested in taking on the kernel and its drivers, the best bet might be the asking for someone to write a PKGBUILD.