[PATCH 0/4] drm/i915: Sprite clipping with related utility funcs to drm core

[ville.syrjala at linux.intel.com]

This series adds a bunch of scaling and clipping related utility stuff to
drm core, and then implementes real clipping for intel sprite planes.

Most of this stuff was in my drm_atomic branch already for quite a while,
but I did do some minor changes here and there.

My glplane test app [1] can now be compiled to use the "legacy" (aka current)
drm plane APIs instead of the atomic page flip/modeset APIs. Without the
atomic page flip support the test is rather slow due the synchronous vblank
waits, and it's also rather ugly (naturally since atomic page flips are needed
to compose pretty pictures). But anyways, since the test can throw the plane
around and off the screen in various ways, I think it's a decent test case
for this code.

[1] https://gitorious.org/vsyrjala/glplane