diff --git a/ui/sdl.c b/ui/sdl.c
index 138ca73407..b89182a2c0 100644
--- a/ui/sdl.c
+++ b/ui/sdl.c
@@ -61,16 +61,24 @@ static SDL_PixelFormat host_format;
 static int scaling_active = 0;
 static Notifier mouse_mode_notifier;
 
+#if 0
+#define DEBUG_SDL
+#endif
+
 static void sdl_update(DisplayChangeListener *dcl,
                        int x, int y, int w, int h)
 {
-    //    printf("updating x=%d y=%d w=%d h=%d\n", x, y, w, h);
     SDL_Rect rec;
     rec.x = x;
     rec.y = y;
     rec.w = w;
     rec.h = h;
 
+#ifdef DEBUG_SDL
+    printf("SDL: Updating x=%d y=%d w=%d h=%d (scaling: %d)\n",
+           x, y, w, h, scaling_active);
+#endif
+
     if (guest_screen) {
         if (!scaling_active) {
             SDL_BlitSurface(guest_screen, &rec, real_screen, &rec);
@@ -89,7 +97,9 @@ static void do_sdl_resize(int width, int height, int bpp)
     int flags;
     SDL_Surface *tmp_screen;
 
-    //    printf("resizing to %d %d\n", w, h);
+#ifdef DEBUG_SDL
+    printf("SDL: Resizing to %dx%d bpp %d\n", width, height, bpp);
+#endif
 
     flags = SDL_HWSURFACE | SDL_ASYNCBLIT | SDL_HWACCEL;
     if (gui_fullscreen) {
@@ -143,6 +153,12 @@ static void sdl_switch(DisplayChangeListener *dcl,
     if (guest_screen != NULL) {
         SDL_FreeSurface(guest_screen);
     }
+
+#ifdef DEBUG_SDL
+    printf("SDL: Creating surface with masks: %08x %08x %08x %08x\n",
+           pf.rmask, pf.gmask, pf.bmask, pf.amask);
+#endif
+
     guest_screen = SDL_CreateRGBSurfaceFrom
         (surface_data(surface),
          surface_width(surface), surface_height(surface),
@@ -486,6 +502,10 @@ static void sdl_scale(int width, int height)
 {
     int bpp = real_screen->format->BitsPerPixel;
 
+#ifdef DEBUG_SDL
+    printf("SDL: Scaling to %dx%d bpp %d\n", width, height, bpp);
+#endif
+
     if (bpp != 16 && bpp != 32) {
         bpp = 32;
     }