[PATCH v4 04/20] drm/atomic: Expand atomic_create_state expectations for drm_private_obj

[Maxime Ripard <mripard@kernel.org>]

The atomic_create_state callback documentation for planes, CRTCs, and
connectors explicitly states the expected behaviour: the returned
state must not be assigned to the object's state pointer, and hardware
must not be touched.

The drm_private_state_funcs.atomic_create_state documentation is
missing this clarification. Add it for consistency.

Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
---
 include/drm/drm_atomic.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/drm/drm_atomic.h b/include/drm/drm_atomic.h
index 1a80a8cdf269..88087910ab1a 100644
--- a/include/drm/drm_atomic.h
+++ b/include/drm/drm_atomic.h
@@ -263,11 +263,14 @@ struct drm_private_state;
 struct drm_private_state_funcs {
 	/**
 	 * @atomic_create_state:
 	 *
 	 * Allocates a pristine, initialized, state for the private
-	 * object and returns it.
+	 * object and returns it. This callback must have no side
+	 * effects: in particular, the returned state must not be
+	 * assigned to the object's state pointer and it must not affect
+	 * the hardware state.
 	 *
 	 * RETURNS:
 	 *
 	 * A new, pristine, private state instance or an error pointer
 	 * on failure.

-- 
2.54.0