Merge branch 'deferred-cursor-move' into '0.17'

Draft: Deferred cursor move

See merge request wlroots/wlroots!4340

types/output/cursor.c

@@ -1,3 +1,4 @@
+#define _POSIX_C_SOURCE 200809L
 #include <assert.h>
 #include <drm_fourcc.h>
 #include <stdlib.h>
@@ -12,6 +13,9 @@
 #include "types/wlr_buffer.h"
 #include "types/wlr_output.h"
 
+#include <time.h>
+#include <util/time.h>
+
 static bool output_set_hardware_cursor(struct wlr_output *output,
 		struct wlr_buffer *buffer, int hotspot_x, int hotspot_y) {
 	if (!output->impl->set_cursor) {
@@ -471,11 +475,10 @@ bool output_cursor_set_texture(struct wlr_output_cursor *cursor,
 	return true;
 }
 
-bool wlr_output_cursor_move(struct wlr_output_cursor *cursor,
-		double x, double y) {
-	// Scale coordinates for the output
-	x *= cursor->output->scale;
-	y *= cursor->output->scale;
+static bool output_cursor_move(struct wlr_output_cursor *cursor,
+		double x, double y, struct timespec *now) {
+	cursor->last_presentation = *now;
+	cursor->deferred = false;
 
 	if (cursor->x == x && cursor->y == y) {
 		return true;
@@ -504,6 +507,76 @@ bool wlr_output_cursor_move(struct wlr_output_cursor *cursor,
 	return cursor->output->impl->move_cursor(cursor->output, (int)x, (int)y);
 }
 
+static bool output_cursor_move_should_defer(struct wlr_output_cursor *cursor,
+		struct timespec *now) {
+	int max_latency = cursor->max_latency;
+
+	if (!max_latency)
+		max_latency = cursor->output->max_cursor_latency;
+
+	if (!max_latency
+		|| !cursor->output->refresh // avoid divide by zero
+		|| cursor->output->adaptive_sync_status != WLR_OUTPUT_ADAPTIVE_SYNC_ENABLED)
+		return false;
+
+	struct timespec delta;
+	int32_t vrr_min = NSEC_PER_SEC / 30; // edid? enforce 30fps minimum for now.
+	timespec_sub(&delta, now, &cursor->last_presentation);
+	if (delta.tv_sec
+		|| delta.tv_nsec >= max_latency
+        || delta.tv_nsec >= vrr_min)
+		return false;
+
+	return true;
+}
+
+bool wlr_output_cursor_move(struct wlr_output_cursor *cursor,
+		double x, double y) {
+	// Scale coordinates for the output
+	x *= cursor->output->scale;
+	y *= cursor->output->scale;
+
+	if (cursor->x == x && cursor->y == y) {
+		return true;
+	}
+
+	struct timespec now;
+	clock_gettime(CLOCK_MONOTONIC, &now);
+
+	if (output_cursor_move_should_defer(cursor, &now)) {
+		cursor->deferred_x = x;
+		cursor->deferred_y = y;
+		cursor->deferred = true;
+		return true;
+	}
+
+	return output_cursor_move(cursor, x, y, &now);
+}
+
+void wlr_output_cursor_move_expired(struct wlr_output_cursor *cursor, struct timespec *now) {
+		if (cursor->deferred && !output_cursor_move_should_defer(cursor, now))
+			output_cursor_move(cursor, cursor->deferred_x, cursor->deferred_y, now);
+}
+
+void wlr_output_cursor_move_any_expired(struct wlr_output *output, struct timespec *now) {
+	struct wlr_output_cursor *cursor;
+	wl_list_for_each(cursor, &output->cursors, link) {
+		wlr_output_cursor_move_expired(cursor, now);
+	}
+}
+
+void wlr_output_cursor_move_all_deferred(struct wlr_output *output, struct timespec *now) {
+	struct wlr_output_cursor *cursor;
+	wl_list_for_each(cursor, &output->cursors, link) {
+		if (cursor->deferred)
+			output_cursor_move(cursor, cursor->deferred_x, cursor->deferred_y, now);
+		else {
+			// Should be on wlr_output?
+			cursor->last_presentation = *now;
+		};
+	}
+}
+
 struct wlr_output_cursor *wlr_output_cursor_create(struct wlr_output *output) {
 	struct wlr_output_cursor *cursor = calloc(1, sizeof(*cursor));
 	if (cursor == NULL) {

types/wlr_cursor.c

@@ -288,6 +288,7 @@ static void cursor_warp_unchecked(struct wlr_cursor *cur,
 
 	struct wlr_cursor_output_cursor *output_cursor;
 	wl_list_for_each(output_cursor, &cur->state->output_cursors, link) {
+		output_cursor->output_cursor->max_latency = cur->max_latency;
 		output_cursor_move(output_cursor);
 	}
 }
@@ -670,6 +671,11 @@ void wlr_cursor_set_surface(struct wlr_cursor *cur, struct wlr_surface *surface,
 	cursor_update_outputs(cur);
 }
 
+void wlr_cursor_set_max_latency(struct wlr_cursor *cur, int max_latency) {
+		cur->max_latency = max_latency;
+		wlr_log(WLR_DEBUG, "setting max_latency %i", max_latency);
+}
+
 static void handle_pointer_motion(struct wl_listener *listener, void *data) {
 	struct wlr_pointer_motion_event *event = data;
 	struct wlr_cursor_device *device =