Creating a DKMS package for a kernel module, dependency on kernel header

Question

Background

I have developed a Linux device driver (ASoC). Now I would like to release it as a DKMS package. The target machine is a Raspberry Pi with Raspbian.

Problem

My source code depends on a header file from the Linux /sound/soc/codecs/ directory. This file does not exist on the target machine.

Workaround 1

I could add the required header file to my DKMS package. But it doesn't feel right, because I think that I should use the header file from the kernel source that the module is being built for (eg. 4.6, 4.7 ...).

Workaround 2

I could tell the end-user to download the whole kernel source (apt-get source ...) before building the module. But installing more than 700MB just because of a single header file does not feel right as well. The package kernel-headers- does not contain the file that I need.

Question

Is there a better solution than the two workarounds? What would you suggest?

Does the header file describes **internals of some kernel's component** (e.g. driver)? So, if internals has been changed between kernel releases, then you need updated version of the header. Or do you want that header only because it **provides some types** (structures), which are useful for your code? — Tsyvarev, Jun 03 '16 at 11:17
@Tsyvarev The header provides some constants and declares a struct, that's what I need. — sergej, Jun 03 '16 at 12:53

score 1 · Answer 1 · answered Jun 03 '16 at 13:18

As the header provides declarations, which doesn't correlate with kernel internals, you may safely take the header from one kernel version, copy it into your package and use it for build against any kernel version. No needs for additional requirement from user to have this header on his machine.

Of course, it is better to retain attributions for this header, but since you use DKMS, your project is likely compatible with Linux kernel's license (GPL).

The other approach - use header from the kernel you build for - is more complex from the view of the user. So it should be used only when it is really needed. E.g., when the header in the question describes some kernel internals which you use in your module. In that case you cannot use single(pre-copied) file for all target kernels.