My biggest kernel patch so far: https://github.com/Darkglass-Electronics/radxa-kernel/commit/cc8f13b0504c290e3cb83a7334e9f1d4e3809c4e

Changing the Linux USB audio gadget to use a very-fast mmap vs the old virtual ALSA card approach, plus also sharing 1 clock for both playback and capture (default implementation uses 1 for playback and 1 for capture, which makes them appear as separate devices - very ugly)

Culmination of 1 month of work, but due to how hacky it is I will have to maintain it forever.
But it's cool, gives the Darkglass Anagram unit a more unique feel!