compositor-drm: drm_output_enable updates unused_crtcs/connectors

Let drm_output_enable() remove the CRTC and the connector from the
unused id arrays.

In the future when a list of drm_heads supersedes unused_connectors
array, the usedness of a connector will be determined by the enabled
state of the output the connector (head) is attached to. The enabled
state is turned on by drm_output_enable(). If unused_crtcs array was
still updated in drm_output_repaint(), the CRTC and connector usedness
would be tracked in different places. Logically the two belong together.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Ian Ray <ian.ray@ge.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>

libweston/compositor-drm.c

@@ -2380,7 +2380,6 @@ drm_output_repaint(struct weston_output *output_base,
 {
 	struct drm_pending_state *pending_state = repaint_data;
 	struct drm_output *output = to_drm_output(output_base);
-	struct drm_backend *backend = to_drm_backend(output_base->compositor);
 	struct drm_output_state *state = NULL;
 	struct drm_plane_state *scanout_state;
 
@@ -2405,10 +2404,6 @@ drm_output_repaint(struct weston_output *output_base,
 	if (!scanout_state || !scanout_state->fb)
 		goto err;
 
-	wl_array_remove_uint32(&backend->unused_connectors,
-			       output->connector_id);
-	wl_array_remove_uint32(&backend->unused_crtcs, output->crtc_id);
-
 	return 0;
 
 err:
@@ -4626,6 +4621,9 @@ drm_output_enable(struct weston_output *base)
 				      &output->scanout_plane->base,
 				      &b->compositor->primary_plane);
 
+	wl_array_remove_uint32(&b->unused_connectors, output->connector_id);
+	wl_array_remove_uint32(&b->unused_crtcs, output->crtc_id);
+
 	weston_log("Output %s, (connector %d, crtc %d)\n",
 		   output->base.name, output->connector_id, output->crtc_id);
 	wl_list_for_each(m, &output->base.mode_list, link)