[PATCH v3 7/8] drm: Connector helper function to release resources

[Dhinakaran Pandiyan]

Having a ->atomic_release callback is useful to release shared resources
that get allocated in compute_config(). This function is expected to be
called in the atomic_check() phase before new resources are acquired.

v2: Moved the caller hunk to this patch (Daniel)

Suggested-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
---
 drivers/gpu/drm/drm_atomic_helper.c      | 19 +++++++++++++++++++
 include/drm/drm_modeset_helper_vtables.h | 13 +++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 8795088..92bd741 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -576,6 +576,25 @@ drm_atomic_helper_check_modeset(struct drm_device *dev,
 		}
 	}
 
+	for_each_connector_in_state(state, connector, connector_state, i) {
+		const struct drm_connector_helper_funcs *conn_funcs;
+		struct drm_crtc_state *crtc_state;
+
+		conn_funcs = connector->helper_private;
+		if (!conn_funcs->atomic_release)
+			continue;
+
+		if (!connector->state->crtc)
+			continue;
+
+		crtc_state = drm_atomic_get_existing_crtc_state(state, connector->state->crtc);
+
+		if (crtc_state->connectors_changed ||
+		    crtc_state->mode_changed ||
+		    (crtc_state->active_changed && !crtc_state->active))
+			conn_funcs->atomic_release(connector, connector_state);
+	}
+
 	return mode_fixup(state);
 }
 EXPORT_SYMBOL(drm_atomic_helper_check_modeset);
diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
index 091c422..394ec0c 100644
--- a/include/drm/drm_modeset_helper_vtables.h
+++ b/include/drm/drm_modeset_helper_vtables.h
@@ -836,6 +836,19 @@ struct drm_connector_helper_funcs {
 	 */
 	struct drm_encoder *(*atomic_best_encoder)(struct drm_connector *connector,
 						   struct drm_connector_state *connector_state);
+
+	/**
+	 * @atomic_release:
+	 *
+	 * This function is used to release shared resources that were
+	 * previously acquired.
+	 *
+	 * NOTE:
+	 *
+	 * This function is called in the check phase of an atomic update.
+	 */
+	void (*atomic_release)(struct drm_connector *connector,
+			       struct drm_connector_state *connector_state);
 };
 
 /**
-- 
2.7.4