From 52222db2550d4fd3f4c0748d73ab8cf39c043761 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Sat, 31 May 2014 11:33:25 -0700
Subject: [PATCH] Fixed SDL error when filtering events after shutdown. This
 can happen when restoring video modes during video system shutdown

---
 src/events/SDL_events.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/events/SDL_events.c b/src/events/SDL_events.c
index 7a98c30218040..28be2ed313f06 100644
--- a/src/events/SDL_events.c
+++ b/src/events/SDL_events.c
@@ -550,7 +550,7 @@ SDL_DelEventWatch(SDL_EventFilter filter, void *userdata)
 void
 SDL_FilterEvents(SDL_EventFilter filter, void *userdata)
 {
-    if (SDL_LockMutex(SDL_EventQ.lock) == 0) {
+    if (SDL_EventQ.lock && SDL_LockMutex(SDL_EventQ.lock) == 0) {
         SDL_EventEntry *entry, *next;
         for (entry = SDL_EventQ.head; entry; entry = next) {
             next = entry->next;