This can happen when we run out of encoders for a multi-crtc modeset, or also when userspace is silly and tries to clone multiple connectors that need the same encoder on the same crtc.
Reported-and-Tested-and-Reviewed-by: Maarten Lankhorst maarten.lankhorst@linux.intel.com Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com Signed-off-by: Daniel Vetter daniel.vetter@intel.com --- drivers/gpu/drm/drm_atomic_helper.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+)
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index d6d80b30f751..aff616dc6caf 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -86,6 +86,27 @@ drm_atomic_helper_plane_changed(struct drm_atomic_state *state, } }
+static bool +check_pending_encoder_assignment(struct drm_atomic_state *state, + struct drm_encoder *new_encoder, + struct drm_connector *new_connector) +{ + struct drm_connector *connector; + struct drm_connector_state *conn_state; + int i; + + for_each_connector_in_state(state, connector, conn_state, i) { + if (conn_state->best_encoder != new_encoder) + continue; + + /* encoder already assigned and we're trying to re-steal it! */ + if (connector->state->best_encoder != conn_state->best_encoder) + return false; + } + + return true; +} + static struct drm_crtc * get_current_crtc_for_encoder(struct drm_device *dev, struct drm_encoder *encoder) @@ -235,6 +256,13 @@ update_connector_routing(struct drm_atomic_state *state, int conn_idx) return 0; }
+ if (!check_pending_encoder_assignment(state, new_encoder, connector)) { + DRM_DEBUG_ATOMIC("Encoder for [CONNECTOR:%d:%s] already assigned\n", + connector->base.id, + connector->name); + return -EINVAL; + } + encoder_crtc = get_current_crtc_for_encoder(state->dev, new_encoder);