[mutter] kms/update: Add unassign_plane() API

[Jonas Ådahl <jadahl src gnome org>]

commit 851024f7300b0b9a996f27ab830d6ac596eaf0f8
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Nov 1 15:23:19 2019 +0100

    kms/update: Add unassign_plane() API
    
    Meant to disable a plane.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/930

 src/backends/native/meta-kms-update.c | 23 +++++++++++++++++++++++
 src/backends/native/meta-kms-update.h |  4 ++++
 2 files changed, 27 insertions(+)
---
diff --git a/src/backends/native/meta-kms-update.c b/src/backends/native/meta-kms-update.c
index c946aa7a2..c2a5cc440 100644
--- a/src/backends/native/meta-kms-update.c
+++ b/src/backends/native/meta-kms-update.c
@@ -102,6 +102,29 @@ meta_kms_update_assign_plane (MetaKmsUpdate        *update,
   return plane_assignment;
 }
 
+MetaKmsPlaneAssignment *
+meta_kms_update_unassign_plane (MetaKmsUpdate *update,
+                                MetaKmsCrtc   *crtc,
+                                MetaKmsPlane  *plane)
+{
+  MetaKmsPlaneAssignment *plane_assignment;
+
+  g_assert (!meta_kms_update_is_sealed (update));
+
+  plane_assignment = g_new0 (MetaKmsPlaneAssignment, 1);
+  *plane_assignment = (MetaKmsPlaneAssignment) {
+    .update = update,
+    .crtc = crtc,
+    .plane = plane,
+    .fb_id = 0,
+  };
+
+  update->plane_assignments = g_list_prepend (update->plane_assignments,
+                                              plane_assignment);
+
+  return plane_assignment;
+}
+
 void
 meta_kms_update_mode_set (MetaKmsUpdate   *update,
                           MetaKmsCrtc     *crtc,
diff --git a/src/backends/native/meta-kms-update.h b/src/backends/native/meta-kms-update.h
index 1b6942f27..bb663addb 100644
--- a/src/backends/native/meta-kms-update.h
+++ b/src/backends/native/meta-kms-update.h
@@ -66,6 +66,10 @@ MetaKmsPlaneAssignment * meta_kms_update_assign_plane (MetaKmsUpdate        *upd
                                                        MetaFixed16Rectangle  src_rect,
                                                        MetaFixed16Rectangle  dst_rect);
 
+MetaKmsPlaneAssignment * meta_kms_update_unassign_plane (MetaKmsUpdate *update,
+                                                         MetaKmsCrtc   *crtc,
+                                                         MetaKmsPlane  *plane);
+
 void meta_kms_update_page_flip (MetaKmsUpdate                 *update,
                                 MetaKmsCrtc                   *crtc,
                                 const MetaKmsPageFlipFeedback *feedback,