drm: Add drm_rotation_simplify()

drm_rotation_simplify() can be used to eliminate unsupported rotation
flags. It will check if any unsupported flags are present, and if so
it will modify the rotation to an alternate form by adding 180 degrees
to rotation angle, and flipping the reflect x and y bits. The hope is
that this identity transform will eliminate the unsupported flags.

Of course that might not result in any more supported rotation, so
the caller is still responsible for checking the result afterwards.

Cc: [email protected]
Signed-off-by: Ville Syrjälä <[email protected]>
Reviewed-by: Imre Deak <[email protected]>
Acked-by: Dave Airlie <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>

0 files changed, 0 insertions, 0 deletions