drm/atomic: Add encoder_mask to crtc_state, v3.

This allows iteration over encoders without requiring connection_mutex.

Changes since v1:
- Add a set_best_encoder helper function and update encoder_mask inside
  it.
Changes since v2:
- Relax the WARN_ON(!crtc), with explanation.
- Call set_best_encoder when connector is moved between crtc's.
- Add some paranoia to steal_encoder to prevent accidentally setting
  best_encoder to NULL.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/56AA200A.6070501@linux.intel.com

1 files changed, 50 insertions, 3 deletions

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 254f6d0..2b430b0 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -125,6 +125,47 @@ get_current_crtc_for_encoder(struct drm_device *dev,
 	return NULL;
 }
 
+static void
+set_best_encoder(struct drm_atomic_state *state,
+		 struct drm_connector_state *conn_state,
+		 struct drm_encoder *encoder)
+{
+	struct drm_crtc_state *crtc_state;
+	struct drm_crtc *crtc;
+
+	if (conn_state->best_encoder) {
+		/* Unset the encoder_mask in the old crtc state. */
+		crtc = conn_state->connector->state->crtc;
+
+		/* A NULL crtc is an error here because we should have
+		 *  duplicated a NULL best_encoder when crtc was NULL.
+		 * As an exception restoring duplicated atomic state
+		 * during resume is allowed, so don't warn when
+		 * best_encoder is equal to encoder we intend to set.
+		 */
+		WARN_ON(!crtc && encoder != conn_state->best_encoder);
+		if (crtc) {
+			crtc_state = drm_atomic_get_existing_crtc_state(state, crtc);
+
+			crtc_state->encoder_mask &=
+				~(1 << drm_encoder_index(conn_state->best_encoder));
+		}
+	}
+
+	if (encoder) {
+		crtc = conn_state->crtc;
+		WARN_ON(!crtc);
+		if (crtc) {
+			crtc_state = drm_atomic_get_existing_crtc_state(state, crtc);
+
+			crtc_state->encoder_mask |=
+				1 << drm_encoder_index(encoder);
+		}
+	}
+
+	conn_state->best_encoder = encoder;
+}
+
 static int
 steal_encoder(struct drm_atomic_state *state,
 	      struct drm_encoder *encoder,
@@ -164,7 +205,10 @@ steal_encoder(struct drm_atomic_state *state,
 		if (IS_ERR(connector_state))
 			return PTR_ERR(connector_state);
 
-		connector_state->best_encoder = NULL;
+		if (connector_state->best_encoder != encoder)
+			continue;
+
+		set_best_encoder(state, connector_state, NULL);
 	}
 
 	return 0;
@@ -212,7 +256,7 @@ update_connector_routing(struct drm_atomic_state *state, int conn_idx)
 				connector->base.id,
 				connector->name);
 
-		connector_state->best_encoder = NULL;
+		set_best_encoder(state, connector_state, NULL);
 
 		return 0;
 	}
@@ -241,6 +285,8 @@ update_connector_routing(struct drm_atomic_state *state, int conn_idx)
 	}
 
 	if (new_encoder == connector_state->best_encoder) {
+		set_best_encoder(state, connector_state, new_encoder);
+
 		DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] keeps [ENCODER:%d:%s], now on [CRTC:%d:%s]\n",
 				 connector->base.id,
 				 connector->name,
@@ -275,7 +321,8 @@ update_connector_routing(struct drm_atomic_state *state, int conn_idx)
 	if (WARN_ON(!connector_state->crtc))
 		return -EINVAL;
 
-	connector_state->best_encoder = new_encoder;
+	set_best_encoder(state, connector_state, new_encoder);
+
 	idx = drm_crtc_index(connector_state->crtc);
 
 	crtc_state = state->crtc_states[idx];