And get stuck on 4.4 kernels for 10 years ? No way !
I'd like to remind some people that old kernels do not get the features improvement of the newer kernels. If the new kernels gain in performance, the old kernels won't. If some DRM stack bugs get fixed through some severe code refactoring job, old kernel won't get these bug fixes unless someone backports the whole patch himself.
Old kernels only get bug fixes for severe bugs, and a few backported improvements from some developers. That's it.
The Rockchip 4.4 kernel is not "optimized". It just integrates some specific Rockchip drivers, that should be ported anyway. However, most of their drivers seemed to rely on IOMMU patches coming from another 3rd-party kernel branch that never got updated anymore... Which is slowing down the porting process.
Meanwhile, I'd like to have everything mainlined ASAP, from kernel patches to software patches, in order to do whatever I want on these boards, without having to deal with outdated vendor-specific packages.