[Intel-gfx] [PATCH 2/2] drm/i915/fbc: Resize CFB in non-full modeset paths

[Chris Wilson]

Quoting José Roberto de Souza (2018-04-06 21:53:49)
> A simple page flip can cause the CFB required size to increase and
> if it is bigger than the currently allocated CFB it needs to be
> resized to activate FBC again.

I would have expected the answer to be to plug into atomic. During the
prepare phase, you evaluate the planes for compatibility with FBC, and
record what actions you plan to take in the commit (including allocating
the next slab of stolen if required). Everything now goes through the
same atomic prepare/commit, so it should be possible to eliminate all
guess work.

Hopefully Maarten can either explain it better or why it shouldn't be
done that at all. ;)
-Chris