diff --git a/src/meson.build b/src/meson.build
index faacb3159..91cf29adb 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -466,6 +466,8 @@ if have_x11_client
'x11/meta-selection-source-x11-private.h',
'x11/meta-startup-notification-x11.c',
'x11/meta-startup-notification-x11.h',
+ 'x11/meta-sync-counter.c',
+ 'x11/meta-sync-counter.h',
'x11/meta-x11-display.c',
'x11/meta-x11-display-private.h',
'x11/meta-x11-errors.c',
diff --git a/src/x11/meta-sync-counter.c b/src/x11/meta-sync-counter.c
new file mode 100644
index 000000000..b05f35a24
--- /dev/null
+++ b/src/x11/meta-sync-counter.c
@@ -0,0 +1,349 @@
+/*
+ * Copyright (C) 2022 Red Hat Inc
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see .
+ *
+ * Author: Carlos Garnacho
+ */
+
+#include "config.h"
+
+#include "meta-sync-counter.h"
+
+#include "core/window-private.h"
+#include "meta/meta-x11-errors.h"
+#include "x11/meta-x11-display-private.h"
+
+void
+meta_sync_counter_init (MetaSyncCounter *sync_counter,
+ MetaWindow *window,
+ Window xwindow)
+{
+ sync_counter->window = window;
+ sync_counter->xwindow = xwindow;
+}
+
+void
+meta_sync_counter_clear (MetaSyncCounter *sync_counter)
+{
+ g_clear_handle_id (&sync_counter->sync_request_timeout_id, g_source_remove);
+ meta_sync_counter_destroy_sync_alarm (sync_counter);
+ sync_counter->window = NULL;
+ sync_counter->xwindow = None;
+}
+
+void
+meta_sync_counter_set_counter (MetaSyncCounter *sync_counter,
+ XSyncCounter counter,
+ gboolean extended)
+{
+ meta_sync_counter_destroy_sync_alarm (sync_counter);
+ sync_counter->sync_request_counter = None;
+
+ sync_counter->sync_request_counter = counter;
+ sync_counter->extended_sync_request_counter = extended;
+
+ if (sync_counter->sync_request_counter != None)
+ {
+ meta_verbose ("Window has _NET_WM_SYNC_REQUEST_COUNTER 0x%lx (extended=%s)",
+ sync_counter->sync_request_counter,
+ sync_counter->extended_sync_request_counter ? "true" : "false");
+ }
+
+ if (sync_counter->extended_sync_request_counter)
+ meta_sync_counter_create_sync_alarm (sync_counter);
+}
+
+void
+meta_sync_counter_create_sync_alarm (MetaSyncCounter *sync_counter)
+{
+ MetaWindow *window = sync_counter->window;
+ MetaX11Display *x11_display = window->display->x11_display;
+ XSyncAlarmAttributes values;
+ XSyncValue init;
+
+ if (sync_counter->sync_request_counter == None ||
+ sync_counter->sync_request_alarm != None)
+ return;
+
+ meta_x11_error_trap_push (x11_display);
+
+ /* In the new (extended style), the counter value is initialized by
+ * the client before mapping the window. In the old style, we're
+ * responsible for setting the initial value of the counter.
+ */
+ if (sync_counter->extended_sync_request_counter)
+ {
+ if (!XSyncQueryCounter (x11_display->xdisplay,
+ sync_counter->sync_request_counter,
+ &init))
+ {
+ meta_x11_error_trap_pop_with_return (x11_display);
+ sync_counter->sync_request_counter = None;
+ return;
+ }
+
+ sync_counter->sync_request_serial =
+ XSyncValueLow32 (init) + ((gint64) XSyncValueHigh32 (init) << 32);
+ }
+ else
+ {
+ XSyncIntToValue (&init, 0);
+ XSyncSetCounter (x11_display->xdisplay,
+ sync_counter->sync_request_counter, init);
+ sync_counter->sync_request_serial = 0;
+ }
+
+ values.trigger.counter = sync_counter->sync_request_counter;
+ values.trigger.test_type = XSyncPositiveComparison;
+
+ /* Initialize to one greater than the current value */
+ values.trigger.value_type = XSyncRelative;
+ XSyncIntToValue (&values.trigger.wait_value, 1);
+
+ /* After triggering, increment test_value by this until
+ * until the test condition is false */
+ XSyncIntToValue (&values.delta, 1);
+
+ /* we want events (on by default anyway) */
+ values.events = True;
+
+ sync_counter->sync_request_alarm = XSyncCreateAlarm (x11_display->xdisplay,
+ XSyncCACounter |
+ XSyncCAValueType |
+ XSyncCAValue |
+ XSyncCATestType |
+ XSyncCADelta |
+ XSyncCAEvents,
+ &values);
+
+ if (meta_x11_error_trap_pop_with_return (x11_display) == Success)
+ {
+ meta_x11_display_register_sync_alarm (x11_display,
+ &sync_counter->sync_request_alarm,
+ window);
+ }
+ else
+ {
+ sync_counter->sync_request_alarm = None;
+ sync_counter->sync_request_counter = None;
+ }
+}
+
+void
+meta_sync_counter_destroy_sync_alarm (MetaSyncCounter *sync_counter)
+{
+ MetaWindow *window = sync_counter->window;
+ MetaX11Display *x11_display = window->display->x11_display;
+
+ if (sync_counter->sync_request_alarm == None)
+ return;
+
+ /* Has to be unregistered _before_ clearing the structure field */
+ meta_x11_display_unregister_sync_alarm (x11_display,
+ sync_counter->sync_request_alarm);
+ XSyncDestroyAlarm (x11_display->xdisplay,
+ sync_counter->sync_request_alarm);
+ sync_counter->sync_request_alarm = None;
+}
+
+gboolean
+meta_sync_counter_has_sync_alarm (MetaSyncCounter *sync_counter)
+{
+ return (!sync_counter->disabled &&
+ sync_counter->sync_request_alarm != None);
+}
+
+static gboolean
+sync_request_timeout (gpointer data)
+{
+ MetaSyncCounter *sync_counter = data;
+ MetaWindow *window = sync_counter->window;
+
+ sync_counter->sync_request_timeout_id = 0;
+
+ /* We have now waited for more than a second for the
+ * application to respond to the sync request
+ */
+ sync_counter->disabled = TRUE;
+
+ /* Reset the wait serial, so we don't continue freezing
+ * window updates
+ */
+ sync_counter->sync_request_wait_serial = 0;
+ meta_compositor_sync_updates_frozen (window->display->compositor, window);
+
+ if (window == window->display->grab_window &&
+ meta_grab_op_is_resizing (window->display->grab_op))
+ {
+ meta_window_update_resize (window,
+ window->display->grab_last_edge_resistance_flags,
+ window->display->grab_latest_motion_x,
+ window->display->grab_latest_motion_y);
+ }
+
+ return G_SOURCE_REMOVE;
+}
+
+void
+meta_sync_counter_send_request (MetaSyncCounter *sync_counter)
+{
+ MetaWindow *window = sync_counter->window;
+ MetaX11Display *x11_display = window->display->x11_display;
+ XClientMessageEvent ev;
+ gint64 wait_serial;
+
+ if (sync_counter->sync_request_counter == None ||
+ sync_counter->sync_request_alarm == None ||
+ sync_counter->sync_request_timeout_id != 0 ||
+ sync_counter->disabled)
+ return;
+
+ /* For the old style of _NET_WM_SYNC_REQUEST_COUNTER, we just have to
+ * increase the value, but for the new "extended" style we need to
+ * pick an even (unfrozen) value sufficiently ahead of the last serial
+ * that we received from the client; the same code still works
+ * for the old style. The increment of 240 is specified by the EWMH
+ * and is (1 second) * (60fps) * (an increment of 4 per frame).
+ */
+ wait_serial = sync_counter->sync_request_serial + 240;
+
+ sync_counter->sync_request_wait_serial = wait_serial;
+
+ ev.type = ClientMessage;
+ ev.window = sync_counter->xwindow;
+ ev.message_type = x11_display->atom_WM_PROTOCOLS;
+ ev.format = 32;
+ ev.data.l[0] = x11_display->atom__NET_WM_SYNC_REQUEST;
+ /* FIXME: meta_display_get_current_time() is bad, but since calls
+ * come from meta_window_move_resize_internal (which in turn come
+ * from all over), I'm not sure what we can do to fix it. Do we
+ * want to use _roundtrip, though?
+ */
+ ev.data.l[1] = meta_display_get_current_time (window->display);
+ ev.data.l[2] = wait_serial & G_GUINT64_CONSTANT (0xffffffff);
+ ev.data.l[3] = wait_serial >> 32;
+ ev.data.l[4] = sync_counter->extended_sync_request_counter ? 1 : 0;
+
+ /* We don't need to trap errors here as we are already
+ * inside an error_trap_push()/pop() pair.
+ */
+ XSendEvent (x11_display->xdisplay,
+ sync_counter->xwindow, False, 0, (XEvent*) &ev);
+
+ /* We give the window 1 sec to respond to _NET_WM_SYNC_REQUEST;
+ * if this time expires, we consider the window unresponsive
+ * and resize it unsynchonized.
+ */
+ sync_counter->sync_request_timeout_id = g_timeout_add (1000,
+ sync_request_timeout,
+ sync_counter);
+ g_source_set_name_by_id (sync_counter->sync_request_timeout_id,
+ "[mutter] sync_request_timeout");
+
+ meta_compositor_sync_updates_frozen (window->display->compositor, window);
+}
+
+void
+meta_sync_counter_update (MetaSyncCounter *sync_counter,
+ int64_t new_counter_value)
+{
+ MetaWindow *window = sync_counter->window;
+ gboolean needs_frame_drawn = FALSE;
+ gboolean no_delay_frame = FALSE;
+
+ COGL_TRACE_BEGIN (MetaWindowSyncRequestCounter, "X11: Sync request counter");
+
+ if (sync_counter->extended_sync_request_counter && new_counter_value % 2 == 0)
+ {
+ needs_frame_drawn = TRUE;
+ no_delay_frame = new_counter_value == sync_counter->sync_request_serial + 1;
+ }
+
+ sync_counter->sync_request_serial = new_counter_value;
+ meta_compositor_sync_updates_frozen (window->display->compositor, window);
+
+ if (new_counter_value >= sync_counter->sync_request_wait_serial &&
+ sync_counter->sync_request_timeout_id)
+ {
+ if (!sync_counter->extended_sync_request_counter ||
+ new_counter_value % 2 == 0)
+ {
+ g_clear_handle_id (&sync_counter->sync_request_timeout_id,
+ g_source_remove);
+ }
+
+ if (window == window->display->grab_window &&
+ meta_grab_op_is_resizing (window->display->grab_op) &&
+ (!sync_counter->extended_sync_request_counter ||
+ new_counter_value % 2 == 0))
+ {
+ meta_topic (META_DEBUG_RESIZING,
+ "Alarm event received last motion x = %d y = %d",
+ window->display->grab_latest_motion_x,
+ window->display->grab_latest_motion_y);
+
+ /* This means we are ready for another configure;
+ * no pointer round trip here, to keep in sync */
+ meta_window_update_resize (window,
+ window->display->grab_last_edge_resistance_flags,
+ window->display->grab_latest_motion_x,
+ window->display->grab_latest_motion_y);
+ }
+ }
+
+ /* If sync was previously disabled, turn it back on and hope
+ * the application has come to its senses (maybe it was just
+ * busy with a pagefault or a long computation).
+ */
+ sync_counter->disabled = FALSE;
+
+ if (needs_frame_drawn)
+ meta_compositor_queue_frame_drawn (window->display->compositor, window,
+ no_delay_frame);
+
+#ifdef COGL_HAS_TRACING
+ if (G_UNLIKELY (cogl_is_tracing_enabled ()))
+ {
+ g_autofree char *description = NULL;
+
+ description =
+ g_strdup_printf ("sync request serial: %" G_GINT64_FORMAT ", "
+ "needs frame drawn: %s",
+ new_counter_value,
+ needs_frame_drawn ? "yes" : "no");
+ COGL_TRACE_DESCRIBE (MetaWindowSyncRequestCounter, description);
+ COGL_TRACE_END (MetaWindowSyncRequestCounter);
+ }
+#endif
+}
+
+gboolean
+meta_sync_counter_is_waiting (MetaSyncCounter *sync_counter)
+{
+ if (sync_counter->extended_sync_request_counter &&
+ sync_counter->sync_request_serial % 2 == 1)
+ return TRUE;
+
+ if (sync_counter->sync_request_serial < sync_counter->sync_request_wait_serial)
+ return TRUE;
+
+ return FALSE;
+}
+
+gboolean
+meta_sync_counter_is_waiting_response (MetaSyncCounter *sync_counter)
+{
+ return sync_counter->sync_request_timeout_id != 0;
+}
diff --git a/src/x11/meta-sync-counter.h b/src/x11/meta-sync-counter.h
new file mode 100644
index 000000000..364bea1e6
--- /dev/null
+++ b/src/x11/meta-sync-counter.h
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2022 Red Hat Inc
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see .
+ *
+ * Author: Carlos Garnacho
+ */
+
+#ifndef META_SYNC_COUNTER_H
+#define META_SYNC_COUNTER_H
+
+#include "meta/window.h"
+
+#include
+#include
+
+typedef struct
+{
+ MetaWindow *window;
+ Window xwindow;
+ /* XSync update counter */
+ XSyncCounter sync_request_counter;
+ int64_t sync_request_serial;
+ int64_t sync_request_wait_serial;
+ guint sync_request_timeout_id;
+ /* alarm monitoring client's _NET_WM_SYNC_REQUEST_COUNTER */
+ XSyncAlarm sync_request_alarm;
+ /* if TRUE, the we have the new form of sync request counter which
+ * also handles application frames */
+ guint extended_sync_request_counter : 1;
+ guint disabled : 1;
+} MetaSyncCounter;
+
+void meta_sync_counter_init (MetaSyncCounter *sync_counter,
+ MetaWindow *window,
+ Window xwindow);
+
+void meta_sync_counter_clear (MetaSyncCounter *sync_counter);
+
+void meta_sync_counter_set_counter (MetaSyncCounter *sync_counter,
+ XSyncCounter counter,
+ gboolean extended);
+
+void meta_sync_counter_create_sync_alarm (MetaSyncCounter *sync_counter);
+
+void meta_sync_counter_destroy_sync_alarm (MetaSyncCounter *sync_counter);
+
+gboolean meta_sync_counter_has_sync_alarm (MetaSyncCounter *sync_counter);
+
+void meta_sync_counter_send_request (MetaSyncCounter *sync_counter);
+
+void meta_sync_counter_update (MetaSyncCounter *sync_counter,
+ int64_t new_counter_value);
+
+gboolean meta_sync_counter_is_waiting (MetaSyncCounter *sync_counter);
+
+gboolean meta_sync_counter_is_waiting_response (MetaSyncCounter *sync_counter);
+
+#endif /* META_SYNC_COUNTER_H */