OSS + ELC EU 2026

While changes to the internal kernel APIs and design are possible, that doesn't mean they are easy.

In preparation for a larger work to make the DRM subsystem support video output pipelines with hot-pluggable components, we have been working for the past two years to change the lifetime of `struct drm_bridge` in the DRM subsystem. This required changing the semantics of a dozen internal APIs and adaptations to more than 50 drivers.

This talk is not about the content of the changes but rather about the process to achieve it: the initial steps to find the best strategy, the continuation to convert all APIs, bugs introduced and reacting to them, working on lots of drivers without the chance to test them, dead ends encountered, tools used, the time required for the whole process, and the community interactions in the whole time span.

The focus will be on lessons learnt and which strategies worked better, and ultimately how to make a similar kind of massive conversion in the most efficient (and least frustrating!) way.