wlr-output-management: implement adaptive sync

Version 4 of the protocol adds support for reporting/setting adaptive
sync state of outputs. Implement these new requests/events in wlroots.

include/wlr/types/wlr_output_management_v1.h

@@ -56,6 +56,7 @@ struct wlr_output_head_v1_state {
 	int32_t x, y;
 	enum wl_output_transform transform;
 	float scale;
+	bool adaptive_sync_enabled;
 };
 
 struct wlr_output_head_v1 {

protocol/wlr-output-management-unstable-v1.xml

@@ -39,7 +39,7 @@
     interface version number is reset.
   </description>
 
-  <interface name="zwlr_output_manager_v1" version="3">
+  <interface name="zwlr_output_manager_v1" version="4">
     <description summary="output device configuration manager">
       This interface is a manager that allows reading and writing the current
       output device configuration.
@@ -125,7 +125,7 @@
     </event>
   </interface>
 
-  <interface name="zwlr_output_head_v1" version="3">
+  <interface name="zwlr_output_head_v1" version="4">
     <description summary="output device">
       A head is an output device. The difference between a wl_output object and
       a head is that heads are advertised even if they are turned off. A head
@@ -338,6 +338,22 @@
         object.
       </description>
     </request>
+
+    <!-- Version 4 additions -->
+
+    <enum name="adaptive_sync_state" since="4">
+      <entry name="disabled" value="0" summary="adaptive sync is disabled"/>
+      <entry name="enabled" value="1" summary="adaptive sync is enabled"/>
+    </enum>
+
+    <event name="adaptive_sync" since="4">
+      <description summary="current adaptive sync state">
+        This event describes whether adaptive sync is currently enabled for
+        the head or not. Adaptive sync is also known as Variable Refresh
+        Rate or VRR.
+      </description>
+      <arg name="state" type="uint" enum="adaptive_sync_state"/>
+    </event>
   </interface>
 
   <interface name="zwlr_output_mode_v1" version="3">
@@ -395,7 +411,7 @@
     </request>
   </interface>
 
-  <interface name="zwlr_output_configuration_v1" version="3">
+  <interface name="zwlr_output_configuration_v1" version="4">
     <description summary="output configuration">
       This object is used by the client to describe a full output configuration.
 
@@ -513,7 +529,7 @@
     </request>
   </interface>
 
-  <interface name="zwlr_output_configuration_head_v1" version="3">
+  <interface name="zwlr_output_configuration_head_v1" version="4">
     <description summary="head configuration">
       This object is used by the client to update a single head's configuration.
 
@@ -526,6 +542,8 @@
       <entry name="invalid_custom_mode" value="3" summary="mode is invalid"/>
       <entry name="invalid_transform" value="4" summary="transform value outside enum"/>
       <entry name="invalid_scale" value="5" summary="scale negative or zero"/>
+      <entry name="invalid_adaptive_sync_state" value="6" since="4"
+        summary="invalid enum value used in the set_adaptive_sync request"/>
     </enum>
 
     <request name="set_mode">
@@ -569,5 +587,15 @@
       </description>
       <arg name="scale" type="fixed"/>
     </request>
+
+    <!-- Version 4 additions -->
+
+    <request name="set_adaptive_sync" since="4">
+      <description summary="enable/disable adaptive sync">
+        This request enables/disables adaptive sync. Adaptive sync is also
+        known as Variable Refresh Rate or VRR.
+      </description>
+      <arg name="state" type="uint" enum="zwlr_output_head_v1.adaptive_sync_state"/>
+    </request>
   </interface>
 </protocol>

types/wlr_output_management_v1.c

@@ -5,7 +5,7 @@
 #include <wlr/util/log.h>
 #include "wlr-output-management-unstable-v1-protocol.h"
 
-#define OUTPUT_MANAGER_VERSION 3
+#define OUTPUT_MANAGER_VERSION 4
 
 enum {
 	HEAD_STATE_ENABLED = 1 << 0,
@@ -13,10 +13,12 @@ enum {
 	HEAD_STATE_POSITION = 1 << 2,
 	HEAD_STATE_TRANSFORM = 1 << 3,
 	HEAD_STATE_SCALE = 1 << 4,
+	HEAD_STATE_ADAPTIVE_SYNC = 1 << 5,
 };
 
 static const uint32_t HEAD_STATE_ALL = HEAD_STATE_ENABLED | HEAD_STATE_MODE |
-	HEAD_STATE_POSITION | HEAD_STATE_TRANSFORM | HEAD_STATE_SCALE;
+	HEAD_STATE_POSITION | HEAD_STATE_TRANSFORM | HEAD_STATE_SCALE |
+	HEAD_STATE_ADAPTIVE_SYNC;
 
 static const struct zwlr_output_head_v1_interface head_impl;
 
@@ -135,6 +137,8 @@ struct wlr_output_configuration_head_v1 *
 	config_head->state.custom_mode.refresh = output->refresh;
 	config_head->state.transform = output->transform;
 	config_head->state.scale = output->scale;
+	config_head->state.adaptive_sync_enabled =
+		output->adaptive_sync_status == WLR_OUTPUT_ADAPTIVE_SYNC_ENABLED;
 	return config_head;
 }
 
@@ -258,12 +262,36 @@ static void config_head_handle_set_scale(struct wl_client *client,
 	config_head->state.scale = scale;
 }
 
+static void config_head_handle_set_adaptive_sync(struct wl_client *client,
+		struct wl_resource *config_head_resource, uint32_t state) {
+	struct wlr_output_configuration_head_v1 *config_head =
+		config_head_from_resource(config_head_resource);
+	if (config_head == NULL) {
+		return;
+	}
+
+	switch (state) {
+	case ZWLR_OUTPUT_HEAD_V1_ADAPTIVE_SYNC_STATE_ENABLED:
+		config_head->state.adaptive_sync_enabled = true;
+		break;
+	case ZWLR_OUTPUT_HEAD_V1_ADAPTIVE_SYNC_STATE_DISABLED:
+		config_head->state.adaptive_sync_enabled = false;
+		break;
+	default:
+		wl_resource_post_error(config_head_resource,
+			ZWLR_OUTPUT_CONFIGURATION_HEAD_V1_ERROR_INVALID_ADAPTIVE_SYNC_STATE,
+			"client requested invalid adaptive sync state %ul", state);
+		break;
+	}
+}
+
 static const struct zwlr_output_configuration_head_v1_interface config_head_impl = {
 	.set_mode = config_head_handle_set_mode,
 	.set_custom_mode = config_head_handle_set_custom_mode,
 	.set_position = config_head_handle_set_position,
 	.set_transform = config_head_handle_set_transform,
 	.set_scale = config_head_handle_set_scale,
+	.set_adaptive_sync = config_head_handle_set_adaptive_sync,
 };
 
 static void config_head_handle_resource_destroy(struct wl_resource *resource) {
@@ -750,6 +778,18 @@ static void head_send_state(struct wlr_output_head_v1 *head,
 		zwlr_output_head_v1_send_scale(head_resource,
 			wl_fixed_from_double(head->state.scale));
 	}
+
+	if ((state & HEAD_STATE_ADAPTIVE_SYNC) &&
+			wl_resource_get_version(head_resource) >=
+			ZWLR_OUTPUT_HEAD_V1_ADAPTIVE_SYNC_SINCE_VERSION) {
+		if (head->state.adaptive_sync_enabled) {
+			zwlr_output_head_v1_send_adaptive_sync(head_resource,
+				ZWLR_OUTPUT_HEAD_V1_ADAPTIVE_SYNC_STATE_ENABLED);
+		} else {
+			zwlr_output_head_v1_send_adaptive_sync(head_resource,
+				ZWLR_OUTPUT_HEAD_V1_ADAPTIVE_SYNC_STATE_DISABLED);
+		}
+	}
 }
 
 static void head_handle_resource_destroy(struct wl_resource *resource) {
@@ -843,6 +883,9 @@ static bool manager_update_head(struct wlr_output_manager_v1 *manager,
 	if (current->scale != next->scale) {
 		state |= HEAD_STATE_SCALE;
 	}
+	if (current->adaptive_sync_enabled != next->adaptive_sync_enabled) {
+		state |= HEAD_STATE_ADAPTIVE_SYNC;
+	}
 
 	// If  a mode was added to wlr_output.modes we need to add the new mode
 	// to the wlr_output_head
@@ -953,4 +996,6 @@ void wlr_output_head_v1_state_apply(
 
 	wlr_output_state_set_scale(output_state, head_state->scale);
 	wlr_output_state_set_transform(output_state, head_state->transform);
+	wlr_output_state_set_adaptive_sync_enabled(output_state,
+		head_state->adaptive_sync_enabled);
 }