[Qemu-devel] [PATCH] don't die if switching to fullscreen mode fails

[Andreas Winkelbauer]

hi,

the attached patch fixes some glitches when switching to fullscreen mode 
using ctrl+alt+f or when booting using -full-screen.

up to now the VM simply dies if one of the following situations occur:
  * user switches from windowed to fullscreen mode using a resolution 
which is too high (meaning higher than the maximum resolution of the 
display)
  * guest boots in fullscreen mode using a resolution which is too high
  * guest is in fullscreen mode and the user switches to a resolution 
which is too high

IMO this is not what the "normal" user would expect.

This patch changes the behaviour as follows:
  * deny switching to fullscreen mode if the resolution is too high and 
print a message to the console
  * use windowed mode as fallback option if we are already in 
fullscreen mode and the new resolution is too high and print a message 
to the console

cheers,
Andi

--- qemu/sdl.c  2007-11-17 18:14:38.000000000 +0100
+++ qemu/sdl.c  2008-02-26 13:32:29.000000000 +0100
@@ -56,46 +56,60 @@ static void sdl_update(DisplayState *ds,
     SDL_UpdateRect(screen, x, y, w, h);
 }
 
-static void sdl_resize(DisplayState *ds, int w, int h)
+static int sdl_resize2(DisplayState *ds, int w, int h, int full_screen, int 
no_frame)
 {
+    SDL_Surface *screen_tmp;
     int flags;
 
-    //    printf("resizing to %d %d\n", w, h);
+    //printf("trying to resize from w=%d h=%d %s to w=%d h=%d %s\n", width, 
height, gui_fullscreen ? "fullscreen" : "windowed", w, h, full_screen ? 
"fullscreen" : "windowed");
 
     flags = SDL_HWSURFACE|SDL_ASYNCBLIT|SDL_HWACCEL;
-    if (gui_fullscreen)
+    if (full_screen)
         flags |= SDL_FULLSCREEN;
-    if (gui_noframe)
+    if (no_frame)
         flags |= SDL_NOFRAME;
 
-    width = w;
-    height = h;
-
- again:
-    screen = SDL_SetVideoMode(w, h, 0, flags);
-    if (!screen) {
-        fprintf(stderr, "Could not open SDL display\n");
-        exit(1);
-    }
-    if (!screen->pixels && (flags & SDL_HWSURFACE) && (flags & 
SDL_FULLSCREEN)) {
-        flags &= ~SDL_HWSURFACE;
-        goto again;
+    if (!(screen_tmp = SDL_SetVideoMode(w, h, 0, flags))) {
+        //fprintf(stderr, "Could not open SDL display (try #1)\n");
+        return -1;
+    } else if (!screen_tmp->pixels && (flags & SDL_HWSURFACE) && (flags & 
SDL_FULLSCREEN)) {
+        screen_tmp = SDL_SetVideoMode(w, h, 0, flags & ~SDL_HWSURFACE);
     }
 
-    if (!screen->pixels) {
-        fprintf(stderr, "Could not open SDL display\n");
-        exit(1);
-    }
-    ds->data = screen->pixels;
-    ds->linesize = screen->pitch;
-    ds->depth = screen->format->BitsPerPixel;
-    if (screen->format->Bshift > screen->format->Rshift) {
-        ds->bgr = 1;
+    if (!screen_tmp || !screen_tmp->pixels) {
+        //fprintf(stderr, "Could not open SDL display (try #2)\n");
+        return -1;
     } else {
-        ds->bgr = 0;
+        screen = screen_tmp;
+        gui_fullscreen = full_screen;
+        gui_noframe = no_frame;
+
+        ds->data = screen->pixels;
+        ds->linesize = screen->pitch;
+        ds->depth = screen->format->BitsPerPixel;
+        if (screen->format->Bshift > screen->format->Rshift) {
+            ds->bgr = 1;
+        } else {
+            ds->bgr = 0;
+        }
+        ds->width = width = w;
+        ds->height = height = h;
+    }
+}
+
+static void sdl_resize(DisplayState *ds, int w, int h)
+{
+    if (sdl_resize2(ds, w, h, gui_fullscreen, gui_noframe) == -1) {
+        fprintf(stderr, "Could not resize display to %d x %d (%s)\n",
+                                               w, h, gui_fullscreen ? 
"fullscreen" : "windowed");
+        
+        /* if we are in fullscreen mode use windowed mode as fallback */
+        if (!gui_fullscreen || sdl_resize2(ds, w, h, 0, gui_noframe) == -1) {
+            exit(1);
+        } else {
+            fprintf(stderr, "Using windowed mode as fallback\n");
+        }
     }
-    ds->width = w;
-    ds->height = h;
 }
 
 /* generic keyboard conversion */
@@ -330,17 +344,21 @@ static void sdl_send_mouse_event(int dz)
 
 static void toggle_full_screen(DisplayState *ds)
 {
-    gui_fullscreen = !gui_fullscreen;
-    sdl_resize(ds, screen->w, screen->h);
-    if (gui_fullscreen) {
-        gui_saved_grab = gui_grab;
-        sdl_grab_start();
-    } else {
-        if (!gui_saved_grab)
-            sdl_grab_end();
+    if (sdl_resize2(ds, screen->w, screen->h, !gui_fullscreen, gui_noframe) != 
-1) {
+        if (gui_fullscreen) {
+            gui_saved_grab = gui_grab;
+            sdl_grab_start();
+        } else {
+            if (!gui_saved_grab)
+                sdl_grab_end();
+        }
+        vga_hw_invalidate();
+        vga_hw_update();
+    }
+    else {
+        fprintf(stderr, "Could not switch to %s mode\n",
+                                               !gui_fullscreen ? "fullscreen" 
: "windowed");
     }
-    vga_hw_invalidate();
-    vga_hw_update();
 }
 
 static void sdl_refresh(DisplayState *ds)
@@ -603,14 +621,14 @@ void sdl_display_init(DisplayState *ds, 
             exit(1);
     }
 
-    if (no_frame)
-        gui_noframe = 1;
-
     flags = SDL_INIT_VIDEO | SDL_INIT_NOPARACHUTE;
     if (SDL_Init (flags)) {
         fprintf(stderr, "Could not initialize SDL - exiting\n");
         exit(1);
     }
+
+    atexit(sdl_cleanup);
+
 #ifndef _WIN32
     /* NOTE: we still want Ctrl-C to work, so we undo the SDL redirections */
     signal(SIGINT, SIG_DFL);
@@ -624,7 +642,10 @@ void sdl_display_init(DisplayState *ds, 
     ds->mouse_set = sdl_mouse_warp;
     ds->cursor_define = sdl_mouse_define;
 
-    sdl_resize(ds, 640, 400);
+    if (sdl_resize2(ds, 640, 400, full_screen, no_frame) == -1) {
+        fprintf(stderr, "Could not resize display in sdl_display_init()\n");
+        exit(1);
+    }
     sdl_update_caption();
     SDL_EnableKeyRepeat(250, 50);
     SDL_EnableUNICODE(1);
@@ -633,9 +654,7 @@ void sdl_display_init(DisplayState *ds, 
     sdl_cursor_hidden = SDL_CreateCursor(&data, &data, 8, 1, 0, 0);
     sdl_cursor_normal = SDL_GetCursor();
 
-    atexit(sdl_cleanup);
-    if (full_screen) {
-        gui_fullscreen = 1;
+    if (gui_fullscreen) {
         gui_fullscreen_initial_grab = 1;
         sdl_grab_start();
     }