Refactor nonblock states.

Preserve nonblock state better across reinits, etc.
Try to keep vsync in RGUI.

driver.c

@@ -255,7 +255,12 @@ static void adjust_system_rates(void)
    RARCH_LOG("Set audio input rate to: %.2f Hz.\n", g_settings.audio.in_rate);
 
    if (driver.video_data)
-      video_set_nonblock_state_func(!g_settings.video.vsync || g_extern.system.force_nonblock);
+   {
+      if (g_extern.system.force_nonblock)
+         video_set_nonblock_state_func(true);
+      else
+         driver_set_nonblock_state(driver.nonblock_state);
+   }
 }
 
 void driver_set_monitor_refresh_rate(float hz)
@@ -267,7 +272,24 @@ void driver_set_monitor_refresh_rate(float hz)
    g_extern.audio_data.orig_src_ratio =
       g_extern.audio_data.src_ratio =
       (double)g_settings.audio.out_rate / g_settings.audio.in_rate;
+}
 
+void driver_set_nonblock_state(bool nonblock)
+{
+   // Only apply non-block-state for video if we're using vsync.
+   if (g_extern.video_active)
+   {
+      bool video_nb = nonblock;
+      if (!g_settings.video.vsync || !g_extern.system.force_nonblock)
+         video_nb = true;
+      video_set_nonblock_state_func(video_nb);
+   }
+
+   if (g_extern.audio_active)
+      audio_set_nonblock_state_func(g_settings.audio.sync ? nonblock : true);
+
+   g_extern.audio_data.chunk_size = nonblock ?
+      g_extern.audio_data.nonblock_chunk_size : g_extern.audio_data.block_chunk_size;
 }
 
 uintptr_t driver_get_current_framebuffer(void)
@@ -347,6 +369,10 @@ void init_drivers(void)
       g_extern.system.hw_render_callback.context_reset();
 
    init_audio();
+
+   // Keep non-throttled state as good as possible.
+   if (driver.nonblock_state)
+      driver_set_nonblock_state(driver.nonblock_state);
 }
 
 void uninit_drivers(void)

driver.h

@@ -416,6 +416,7 @@ typedef struct driver
 #endif
    bool stdin_claimed;
    bool block_hotkey;
+   bool nonblock_state;
 
    // Opaque handles to currently running window.
    // Used by e.g. input drivers which bind to a window.
@@ -460,6 +461,7 @@ void init_audio(void);
 void uninit_audio(void);
 
 void driver_set_monitor_refresh_rate(float hz);
+void driver_set_nonblock_state(bool nonblock);
 
 // Used by RETRO_ENVIRONMENT_SET_HW_RENDER.
 uintptr_t driver_get_current_framebuffer(void);

frontend/frontend.c

@@ -83,7 +83,10 @@ int main(int argc, char *argv[])
       else if (g_extern.lifecycle_mode_state & (1ULL << MODE_MENU))
       {
          g_extern.lifecycle_mode_state |= 1ULL << MODE_MENU_PREINIT;
+         // Menu should always run with vsync on.
+         video_set_nonblock_state_func(false);
          while (menu_iterate());
+         driver_set_nonblock_state(driver.nonblock_state);
          g_extern.lifecycle_mode_state &= ~(1ULL << MODE_MENU);
       }
       else

retroarch.c

@@ -49,38 +49,24 @@
 #define RARCH_PERFORMANCE_MODE
 #endif
 
-// To avoid continous switching if we hold the button down, we require that the button must go from pressed, unpressed back to pressed to be able to toggle between then.
+// To avoid continous switching if we hold the button down, we require that the button must go from pressed,
+// unpressed back to pressed to be able to toggle between then.
 static void check_fast_forward_button(void)
 {
    bool new_button_state = input_key_pressed_func(RARCH_FAST_FORWARD_KEY);
    bool new_hold_button_state = input_key_pressed_func(RARCH_FAST_FORWARD_HOLD_KEY);
-   bool update_sync = false;
    static bool old_button_state = false;
    static bool old_hold_button_state = false;
-   static bool syncing_state = false;
 
    if (new_button_state && !old_button_state)
    {
-      syncing_state = !syncing_state;
-      update_sync = true;
+      driver.nonblock_state = !driver.nonblock_state;
+      driver_set_nonblock_state(driver.nonblock_state);
    }
    else if (old_hold_button_state != new_hold_button_state)
    {
-      syncing_state = new_hold_button_state;
-      update_sync = true;
-   }
-
-   if (update_sync)
-   {
-      // Only apply non-block-state for video if we're using vsync.
-      if (g_extern.video_active && g_settings.video.vsync && !g_extern.system.force_nonblock)
-         video_set_nonblock_state_func(syncing_state);
-
-      if (g_extern.audio_active)
-         audio_set_nonblock_state_func(g_settings.audio.sync ? syncing_state : true);
-
-      g_extern.audio_data.chunk_size =
-         syncing_state ? g_extern.audio_data.nonblock_chunk_size : g_extern.audio_data.block_chunk_size;
+      driver.nonblock_state = new_hold_button_state;
+      driver_set_nonblock_state(driver.nonblock_state);
    }
 
    old_button_state = new_button_state;