[mutter] monitor-manager/native: Get CRTC gamma from cache if available

[Marge Bot <marge-bot src gnome org>]

commit 23a530cb09b4ac65bd904787b0eafa9022e62ac7
Author: Jonas Ådahl <jadahl gmail com>
Date:   Mon Jun 14 18:01:21 2021 +0200

    monitor-manager/native: Get CRTC gamma from cache if available
    
    Right now gamma is set only via the D-Bus API (from gsd-color), but the
    actual gamma isn't right after SetCrtcGamma(), meaning if one would call
    GetCrtcGamma() right after setting it, one would get the old result.
    Avoid this by getting the "current" CRTC gamma from the cache we manage.
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2159>

 src/backends/native/meta-monitor-manager-native.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)
---
diff --git a/src/backends/native/meta-monitor-manager-native.c 
b/src/backends/native/meta-monitor-manager-native.c
index 10ac0810e6..0fa4b02e0e 100644
--- a/src/backends/native/meta-monitor-manager-native.c
+++ b/src/backends/native/meta-monitor-manager-native.c
@@ -379,12 +379,28 @@ meta_monitor_manager_native_get_crtc_gamma (MetaMonitorManager  *manager,
                                             unsigned short     **green,
                                             unsigned short     **blue)
 {
+  MetaMonitorManagerNative *manager_native =
+    META_MONITOR_MANAGER_NATIVE (manager);
+  MetaCrtcKms *crtc_kms = META_CRTC_KMS (crtc);
+  MetaKmsCrtcGamma *crtc_gamma;
   MetaKmsCrtc *kms_crtc;
   const MetaKmsCrtcState *crtc_state;
 
   g_return_if_fail (META_IS_CRTC_KMS (crtc));
 
-  kms_crtc = meta_crtc_kms_get_kms_crtc (META_CRTC_KMS (crtc));
+  crtc_gamma =
+    meta_monitor_manager_native_get_cached_crtc_gamma (manager_native,
+                                                       crtc_kms);
+  if (crtc_gamma)
+    {
+      *size = crtc_gamma->size;
+      *red = g_memdup2 (crtc_gamma->red, *size * sizeof **red);
+      *green = g_memdup2 (crtc_gamma->green, *size * sizeof **green);
+      *blue = g_memdup2 (crtc_gamma->blue, *size * sizeof **blue);
+      return;
+    }
+
+  kms_crtc = meta_crtc_kms_get_kms_crtc (crtc_kms);
   crtc_state = meta_kms_crtc_get_current_state (kms_crtc);
 
   *size = crtc_state->gamma.size;