[RFC weston 00/14] Atomic modesetting support

[Bryce Harrington]

On Thu, May 21, 2015 at 08:28:57AM +0100, Daniel Stone wrote:
> Hi all,
> This patchset is an experimental/RFC implementation of atomic modesetting
> for Weston, as a proof-of-concept for the overall kernel API. It still
> definitely has some rough edges, and safe to say it isn't 1.8 material,
> but might be useful to look at regardless, especially for those of you
> interested in compositor-drm internals.
> 
> This is largely based on Pekka's original work, and Louis-Francis's
> work built on that, but with major changes since in the handling of
> planes. compositor-drm now looks much more like a universal-plane user
> internally; the major change from Pekka's branch is that the primary and
> cursor planes are no longer so extensively special-cased.
> 
> These patches are essentially jointly authored between the three of us;
> some of them have changed ownership along the way due to the amount of
> rewriting performed, as well as splitting.
> 
> At the moment, this has only been validated on i915, using Maarten
> Lankhorst's unify-flip-modeset branch, plus other changes to actually
> expose atomic modesetting to userspace.

This is important code and thus should have test cases.  However, those
will be hard to add after the fact, since they'll probably require a
mock kernel, and thus may require some design modifications to permit
easier testing.

I think you should consider testability in the design of this;
otherwise, it's likely going to be difficult to add tests here after the
fact.

Bryce