feat(hyprland): make gamemode VRR toggle opt-in per host

The gamemode start/end hooks hardcoded a misc:vrr keyword directly in
the shared hyprland module, with no way for a host to opt out. Any
future host enabling Hyprland + gamemode would inherit VRR toggling
regardless of whether its displays support VRR.

Add khanelinix.programs.graphical.wms.hyprland.gamemode.vrr.enable and
only emit the misc:vrr hyprctl keyword when it's set. Also fixes the
existing behavior where the start-hook forced VRR off during gameplay
(misc:vrr 0) while the end-hook only turned it back on (misc:vrr 2) on
exit — both hooks now use the same value when the option is enabled.

Enabled on khanelinix, whose Odyssey G9 (DP-1) supports VRR.

Author: khaneliman

modules/nixos/programs/graphical/wms/hyprland/default.nix

@@ -40,6 +40,7 @@ in
         "Custom configuration files that can be used to override the default files.";
     customFiles = mkOpt attrs { } "Custom files that can be used to override the default files.";
     wallpaper = mkOpt (nullOr package) null "The wallpaper to display.";
+    gamemode.vrr.enable = lib.mkEnableOption "toggling Hyprland VRR mode during gamemode (only for VRR-capable displays)";
   };
 
   config = mkIf cfg.enable {
@@ -106,16 +107,18 @@ in
                 echo "=== Gamemode Start: $(date) ===" > "$LOG_FILE"
 
                 hyprctl --batch '${
-                  lib.concatStringsSep " " [
-                    "keyword animations:enabled 0;"
-                    "keyword decoration:shadow:enabled 0;"
-                    "keyword decoration:blur:enabled 0;"
-                    "keyword decoration:active_opacity 1.0;"
-                    "keyword decoration:inactive_opacity 1.0;"
-                    "keyword decoration:fullscreen_opacity 1.0;"
-                    "keyword debug:vfr 0;"
-                    "keyword misc:vrr 0"
-                  ]
+                  lib.concatStringsSep " " (
+                    [
+                      "keyword animations:enabled 0;"
+                      "keyword decoration:shadow:enabled 0;"
+                      "keyword decoration:blur:enabled 0;"
+                      "keyword decoration:active_opacity 1.0;"
+                      "keyword decoration:inactive_opacity 1.0;"
+                      "keyword decoration:fullscreen_opacity 1.0;"
+                      "keyword debug:vfr 0;"
+                    ]
+                    ++ lib.optional cfg.gamemode.vrr.enable "keyword misc:vrr 2"
+                  )
                 }'
 
                 echo "Setting kitty opacity to 1.0..." >> "$LOG_FILE"
@@ -157,16 +160,18 @@ in
                 echo "=== Gamemode End: $(date) ===" > "$LOG_FILE"
 
                 hyprctl --batch '${
-                  lib.concatStringsSep " " [
-                    "keyword animations:enabled 1;"
-                    "keyword decoration:shadow:enabled 1;"
-                    "keyword decoration:blur:enabled 1;"
-                    "keyword decoration:active_opacity 0.95;"
-                    "keyword decoration:inactive_opacity 0.9;"
-                    "keyword decoration:fullscreen_opacity 1.0;"
-                    "keyword debug:vfr 1;"
-                    "keyword misc:vrr 2"
-                  ]
+                  lib.concatStringsSep " " (
+                    [
+                      "keyword animations:enabled 1;"
+                      "keyword decoration:shadow:enabled 1;"
+                      "keyword decoration:blur:enabled 1;"
+                      "keyword decoration:active_opacity 0.95;"
+                      "keyword decoration:inactive_opacity 0.9;"
+                      "keyword decoration:fullscreen_opacity 1.0;"
+                      "keyword debug:vfr 1;"
+                    ]
+                    ++ lib.optional cfg.gamemode.vrr.enable "keyword misc:vrr 2"
+                  )
                 }'
 
                 echo "Restoring kitty opacity to 0.90..." >> "$LOG_FILE"

systems/x86_64-linux/khanelinix/default.nix

@@ -56,7 +56,10 @@ in
 
       wms = mkMerge [
         {
-          hyprland.enable = true;
+          hyprland = {
+            enable = true;
+            gamemode.vrr.enable = true; # Odyssey G9 (DP-1) supports VRR
+          };
           niri = {
             enable = true;
             package = pkgs.niri-unstable;