Index: src/video/quartz/SDL_QuartzVideo.h
===================================================================
--- src/video/quartz/SDL_QuartzVideo.h	(revision 2990)
+++ src/video/quartz/SDL_QuartzVideo.h	(working copy)
@@ -80,6 +80,7 @@
 /* Main driver structure to store required state information */
 typedef struct SDL_PrivateVideoData {
 
+    BOOL               allow_screensaver;  /* 0 == disable screensaver */
     CGDirectDisplayID  display;            /* 0 == main display (only support single display) */
     CFDictionaryRef    mode;               /* current mode of the display */
     CFDictionaryRef    save_mode;          /* original mode of the display */
@@ -127,6 +128,7 @@
 #define display_id (this->hidden->display)
 #define mode (this->hidden->mode)
 #define save_mode (this->hidden->save_mode)
+#define allow_screensaver (this->hidden->allow_screensaver)
 #define mode_list (this->hidden->mode_list)
 #define palette (this->hidden->palette)
 #define gl_context (this->hidden->gl_context)
Index: src/video/quartz/SDL_QuartzEvents.m
===================================================================
--- src/video/quartz/SDL_QuartzEvents.m	(revision 2990)
+++ src/video/quartz/SDL_QuartzEvents.m	(working copy)
@@ -734,11 +734,13 @@
         return;  /* don't do anything if there's no screen surface. */
 
     /* Update activity every five seconds to prevent screensaver. --ryan. */
-    nowTicks = SDL_GetTicks();
-    if ((nowTicks - screensaverTicks) > 5000)
-    {
-        UpdateSystemActivity(UsrActivity);
-        screensaverTicks = nowTicks;
+    if (!allow_screensaver) {
+        nowTicks = SDL_GetTicks();
+        if ((nowTicks - screensaverTicks) > 5000)
+        {
+            UpdateSystemActivity(UsrActivity);
+            screensaverTicks = nowTicks;
+        }
     }
 
     pool = [ [ NSAutoreleasePool alloc ] init ];
Index: src/video/quartz/SDL_QuartzVideo.m
===================================================================
--- src/video/quartz/SDL_QuartzVideo.m	(revision 2990)
+++ src/video/quartz/SDL_QuartzVideo.m	(working copy)
@@ -169,12 +169,17 @@
 
 static int QZ_VideoInit (_THIS, SDL_PixelFormat *video_format) {
 
+    const char *env = NULL;
+
     /* Initialize the video settings; this data persists between mode switches */
     display_id = kCGDirectMainDisplay;
     save_mode  = CGDisplayCurrentMode    (display_id);
     mode_list  = CGDisplayAvailableModes (display_id);
     palette    = CGPaletteCreateDefaultColorPalette ();
 
+    env = SDL_getenv("SDL_VIDEO_ALLOW_SCREENSAVER");
+    allow_screensaver = ( env && SDL_atoi(env) ) ? YES : NO;
+
     /* Gather some information that is useful to know about the display */
     CFNumberGetValue (CFDictionaryGetValue (save_mode, kCGDisplayBitsPerPixel),
                       kCFNumberSInt32Type, &device_bpp);
Index: src/video/x11/SDL_x11events.c
===================================================================
--- src/video/x11/SDL_x11events.c	(revision 2990)
+++ src/video/x11/SDL_x11events.c	(working copy)
@@ -1138,7 +1138,15 @@
 
 void X11_DisableScreenSaver(Display *display)
 {
+    const char *env = NULL;
 	int timeout, interval, prefer_blank, allow_exp;
+
+	/* Allow environment override */
+	env = SDL_getenv("SDL_VIDEO_ALLOW_SCREENSAVER");
+	if ( env && SDL_atoi(env) ) {
+		return;
+	}
+
 	XGetScreenSaver(display, &timeout, &interval, &prefer_blank, &allow_exp);
 	timeout = 0;
 	XSetScreenSaver(display, timeout, interval, prefer_blank, allow_exp);
@@ -1155,7 +1163,15 @@
 
 void X11_RestoreScreenSaver(Display *display, int saved_timeout, BOOL dpms)
 {
+    const char *env = NULL;
 	int timeout, interval, prefer_blank, allow_exp;
+
+	/* Allow environment override */
+	env = SDL_getenv("SDL_VIDEO_ALLOW_SCREENSAVER");
+	if ( env && SDL_atoi(env) ) {
+		return;
+	}
+
 	XGetScreenSaver(display, &timeout, &interval, &prefer_blank, &allow_exp);
 	timeout = saved_timeout;
 	XSetScreenSaver(display, timeout, interval, prefer_blank, allow_exp);