Thanks for the detailed write-up. I suppose there's another part coming so I don't want to get too deep into discussion just yet, but one part in particular caught my eye:

On Sat, Oct 14, 2017 at 7:20 AM, Stefan Tauner <stefan.tauner@gmx.at> wrote:

While there was a bunch of patches that have been piled up back then it
was less of a problem then the increasing divergence between the
chromiumos fork and upstream. Thus we have discussed ways to converge
that (by pulling changes mainly from upstream into chromium but also
vice versa) and also increase the pace of merging stuff into upstream
later. This was still with no intention to switch to git because of
Carl-Daniel's concerns.

I'm surprised that you think that chromiumos's divergence is a *worse* problem than the huge backlog of upstream patches. The chromiumos fork is self-contained, has its own review system, its own testing, and is targeted at a narrow set of devices. I don't understand how it could have been a problem for upstream and would be interested if you can elaborate on this point.

FWIW I did try pushing some features from chromiumos to upstream, but like other patches they never really got anywhere. I also tried working with Carl-Daniel for a couple months to sync the trees, but that effort didn't get very far.