From e72baac97d2ddc520da255c006fdb6fb4941cc84 Mon Sep 17 00:00:00 2001
From: Dor Askayo <dor.askayo@gmail.com>
Date: Tue, 20 Jun 2023 22:53:43 +0300
Subject: [PATCH] settings: Add experimental feature for variable refresh rate

Require the "variable-refresh-rate" keyword under the
"experimental-features" gsetting to enable the feature for now.

It would no longer be required once the experience with variable
refresh rate is good enough for general use and handles all common
use cases well.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1154>
---
 data/org.gnome.mutter.gschema.xml.in | 7 +++++++
 src/backends/meta-settings-private.h | 1 +
 src/backends/meta-settings.c         | 2 ++
 3 files changed, 10 insertions(+)

diff --git a/data/org.gnome.mutter.gschema.xml.in b/data/org.gnome.mutter.gschema.xml.in
index fa8cf95dd..92c97b12e 100644
--- a/data/org.gnome.mutter.gschema.xml.in
+++ b/data/org.gnome.mutter.gschema.xml.in
@@ -4,6 +4,7 @@
     <value nick="scale-monitor-framebuffer" value="1"/>
     <value nick="kms-modifiers" value="2"/>
     <value nick="autoclose-xwayland" value="4"/>
+    <value nick="variable-refresh-rate" value="8"/>
   </flags>
 
   <schema id="org.gnome.mutter" path="/org/gnome/mutter/"
@@ -129,6 +130,12 @@
                                         relevant X11 clients are gone.
                                         Requires a restart.
 
+        • “variable-refresh-rate”     — makes mutter dynamically adjust the
+                                        refresh rate of the monitor when
+                                        applicable if supported by the monitor,
+                                        GPU and DRM driver. Configurable in
+                                        Settings. Requires a restart.
+
       </description>
     </key>
 
diff --git a/src/backends/meta-settings-private.h b/src/backends/meta-settings-private.h
index ca14ce67c..afbba054a 100644
--- a/src/backends/meta-settings-private.h
+++ b/src/backends/meta-settings-private.h
@@ -31,6 +31,7 @@ typedef enum _MetaExperimentalFeature
   META_EXPERIMENTAL_FEATURE_SCALE_MONITOR_FRAMEBUFFER = (1 << 0),
   META_EXPERIMENTAL_FEATURE_KMS_MODIFIERS  = (1 << 1),
   META_EXPERIMENTAL_FEATURE_AUTOCLOSE_XWAYLAND  = (1 << 2),
+  META_EXPERIMENTAL_FEATURE_VARIABLE_REFRESH_RATE = (1 << 3),
 } MetaExperimentalFeature;
 
 typedef enum _MetaXwaylandExtension
diff --git a/src/backends/meta-settings.c b/src/backends/meta-settings.c
index 486ac5abb..3703b23b0 100644
--- a/src/backends/meta-settings.c
+++ b/src/backends/meta-settings.c
@@ -294,6 +294,8 @@ experimental_features_handler (GVariant *features_variant,
         feature = META_EXPERIMENTAL_FEATURE_KMS_MODIFIERS;
       else if (g_str_equal (feature_str, "autoclose-xwayland"))
         feature = META_EXPERIMENTAL_FEATURE_AUTOCLOSE_XWAYLAND;
+      else if (g_str_equal (feature_str, "variable-refresh-rate"))
+        feature = META_EXPERIMENTAL_FEATURE_VARIABLE_REFRESH_RATE;
 
       if (feature)
         g_message ("Enabling experimental feature '%s'", feature_str);