ui: Deliver refresh rate via QemuUIInfo

This change adds a new member, refresh_rate to QemuUIInfo in
include/ui/console.h. It represents the refresh rate of the
physical display backend, and it is more appropriate than
GUI update interval as the refresh rate which the emulated device
reports:
- sdl may set GUI update interval shorter than the refresh rate
  of the physical display to respond to user-generated events.
- sdl and vnc aggressively changes GUI update interval, but
  a guests is typically not designed to respond to frequent
  refresh rate changes, or frequent "display mode" changes in
  general. The frequency of refresh rate changes of the physical
  display backend matches better to the guest's expectation.

QemuUIInfo also has other members representing "display mode",
which makes it suitable for refresh rate representation. It has
a throttling of update notifications, and prevents frequent changes
of the display mode.

Signed-off-by: Akihiko Odaki <akihiko.odaki@gmail.com>
Message-Id: <20220226115516.59830-3-akihiko.odaki@gmail.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 26 insertions, 19 deletions

diff --git a/ui/gtk.c b/ui/gtk.c
index c57c36749e..2a791dd2aa 100644
--- a/ui/gtk.c
+++ b/ui/gtk.c
@@ -710,11 +710,20 @@ static gboolean gd_window_close(GtkWidget *widget, GdkEvent *event,
     return TRUE;
 }
 
-static void gd_set_ui_info(VirtualConsole *vc, gint width, gint height)
+static void gd_set_ui_refresh_rate(VirtualConsole *vc, int refresh_rate)
 {
     QemuUIInfo info;
 
-    memset(&info, 0, sizeof(info));
+    info = *dpy_get_ui_info(vc->gfx.dcl.con);
+    info.refresh_rate = refresh_rate;
+    dpy_set_ui_info(vc->gfx.dcl.con, &info, true);
+}
+
+static void gd_set_ui_size(VirtualConsole *vc, gint width, gint height)
+{
+    QemuUIInfo info;
+
+    info = *dpy_get_ui_info(vc->gfx.dcl.con);
     info.width = width;
     info.height = height;
     dpy_set_ui_info(vc->gfx.dcl.con, &info, true);
@@ -738,33 +747,32 @@ static void gd_resize_event(GtkGLArea *area,
 {
     VirtualConsole *vc = (void *)opaque;
 
-    gd_set_ui_info(vc, width, height);
+    gd_set_ui_size(vc, width, height);
 }
 
 #endif
 
-/*
- * If available, return the update interval of the monitor in ms,
- * else return 0 (the default update interval).
- */
-int gd_monitor_update_interval(GtkWidget *widget)
+void gd_update_monitor_refresh_rate(VirtualConsole *vc, GtkWidget *widget)
 {
 #ifdef GDK_VERSION_3_22
     GdkWindow *win = gtk_widget_get_window(widget);
+    int refresh_rate;
 
     if (win) {
         GdkDisplay *dpy = gtk_widget_get_display(widget);
         GdkMonitor *monitor = gdk_display_get_monitor_at_window(dpy, win);
-        int refresh_rate = gdk_monitor_get_refresh_rate(monitor); /* [mHz] */
-
-        if (refresh_rate) {
-            /* T = 1 / f = 1 [s*Hz] / f = 1000*1000 [ms*mHz] / f */
-            return MIN(1000 * 1000 / refresh_rate,
-                       GUI_REFRESH_INTERVAL_DEFAULT);
-        }
+        refresh_rate = gdk_monitor_get_refresh_rate(monitor); /* [mHz] */
+    } else {
+        refresh_rate = 0;
     }
+
+    gd_set_ui_refresh_rate(vc, refresh_rate);
+
+    /* T = 1 / f = 1 [s*Hz] / f = 1000*1000 [ms*mHz] / f */
+    vc->gfx.dcl.update_interval = refresh_rate ?
+        MIN(1000 * 1000 / refresh_rate, GUI_REFRESH_INTERVAL_DEFAULT) :
+        GUI_REFRESH_INTERVAL_DEFAULT;
 #endif
-    return 0;
 }
 
 static gboolean gd_draw_event(GtkWidget *widget, cairo_t *cr, void *opaque)
@@ -801,8 +809,7 @@ static gboolean gd_draw_event(GtkWidget *widget, cairo_t *cr, void *opaque)
         return FALSE;
     }
 
-    vc->gfx.dcl.update_interval =
-        gd_monitor_update_interval(vc->window ? vc->window : s->window);
+    gd_update_monitor_refresh_rate(vc, vc->window ? vc->window : s->window);
 
     fbw = surface_width(vc->gfx.ds);
     fbh = surface_height(vc->gfx.ds);
@@ -1691,7 +1698,7 @@ static gboolean gd_configure(GtkWidget *widget,
 {
     VirtualConsole *vc = opaque;
 
-    gd_set_ui_info(vc, cfg->width, cfg->height);
+    gd_set_ui_size(vc, cfg->width, cfg->height);
     return FALSE;
 }