[Qemu-devel] [PATCH resend] sdl: Reverse support for video mode setting

[Lei Li <lilei@linux.vnet.ibm.com>]

Currently, If the setting of video mode failed, qemu will exit. It
should go back to the previous setting if the new screen resolution
failed. This patch fixes LP#1216368, add support to revert to existing
surface for the failure of video mode setting.

Reported-by: Sascha Krissler <sascha@srlabs.de>
Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
---
 ui/sdl.c |   23 +++++++++++++++++++----
 1 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/ui/sdl.c b/ui/sdl.c
index 39a42d6..9d8583c 100644
--- a/ui/sdl.c
+++ b/ui/sdl.c
@@ -86,6 +86,7 @@ static void sdl_update(DisplayChangeListener *dcl,
 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);
 
@@ -98,12 +99,26 @@ static void do_sdl_resize(int width, int height, int bpp)
     if (gui_noframe)
         flags |= SDL_NOFRAME;
 
-    real_screen = SDL_SetVideoMode(width, height, bpp, flags);
+    tmp_screen = SDL_SetVideoMode(width, height, bpp, flags);
     if (!real_screen) {
-	fprintf(stderr, "Could not open SDL display (%dx%dx%d): %s\n", width, 
-		height, bpp, SDL_GetError());
-        exit(1);
+        if (!tmp_screen) {
+            fprintf(stderr, "Could not open SDL display (%dx%dx%d): %s\n",
+                    width, height, bpp, SDL_GetError());
+            exit(1);
+        }
+    } else {
+        /*
+         * Revert to the previous video mode if the change of resizing or
+         * resolution failed.
+         */
+        if (!tmp_screen) {
+            fprintf(stderr, "Failed to set SDL display (%dx%dx%d): %s\n",
+                    width, height, bpp, SDL_GetError());
+            return;
+        }
     }
+
+    real_screen = tmp_screen;
 }
 
 static void sdl_switch(DisplayChangeListener *dcl,
-- 
1.7.7.6