[PATCH 05/29] drm/atomic_state_helper: Fix bridge state initialization

[Maxime Ripard <mripard@kernel.org>]

Bridges implement their state using a drm_private_obj and an
hand-crafted reset implementation.

Since drm_private_obj doesn't have a set of reset helper like the other
states, __drm_atomic_helper_bridge_reset() was initializing both the
drm_private_state and the drm_bridge_state structures.

This initialization however was missing the drm_private_state.obj
pointer to the drm_private_obj the state was allocated for, creating a
NULL pointer dereference when trying to access it.

Fixes: 751465913f04 ("drm/bridge: Add a drm_bridge_state object")
Signed-off-by: Maxime Ripard <mripard@kernel.org>
---
 drivers/gpu/drm/drm_atomic_state_helper.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c
index 7142e163e618ea0d7d9d828e1bd9ff2a6ec0dfeb..b962c342b16aabf4e3bea52a914e5deb1c2080ce 100644
--- a/drivers/gpu/drm/drm_atomic_state_helper.c
+++ b/drivers/gpu/drm/drm_atomic_state_helper.c
@@ -707,10 +707,17 @@ void drm_atomic_helper_connector_destroy_state(struct drm_connector *connector,
 	__drm_atomic_helper_connector_destroy_state(state);
 	kfree(state);
 }
 EXPORT_SYMBOL(drm_atomic_helper_connector_destroy_state);
 
+static void __drm_atomic_helper_private_obj_reset(struct drm_private_obj *obj,
+						  struct drm_private_state *state)
+{
+	memset(state, 0, sizeof(*state));
+	state->obj = obj;
+}
+
 /**
  * __drm_atomic_helper_private_obj_duplicate_state - copy atomic private state
  * @obj: CRTC object
  * @state: new private object state
  *
@@ -796,10 +803,11 @@ EXPORT_SYMBOL(drm_atomic_helper_bridge_destroy_state);
  */
 void __drm_atomic_helper_bridge_reset(struct drm_bridge *bridge,
 				      struct drm_bridge_state *state)
 {
 	memset(state, 0, sizeof(*state));
+	__drm_atomic_helper_private_obj_reset(&bridge->base, &state->base);
 	state->bridge = bridge;
 }
 EXPORT_SYMBOL(__drm_atomic_helper_bridge_reset);
 
 /**

-- 
2.50.1