smoother sdl display & mouse

diff -ur kvm-27.orig/qemu/sdl.c kvm-27/qemu/sdl.c
@@ -43,6 +43,7 @@
 static SDL_Cursor *sdl_cursor_normal;
 static SDL_Cursor *sdl_cursor_hidden;
 static int absolute_enabled = 0;
+static int decimate_counter = 0;
 
 static void sdl_update(DisplayState *ds, int x, int y, int w, int h)
 {

@@ -321,7 +322,10 @@
         sdl_update_caption();
     }
 
-    vga_hw_update();
+    if (decimate_counter == 0)
+	vga_hw_update();
+
+    decimate_counter = (decimate_counter + 1) % sdl_decimate;
 
     while (SDL_PollEvent(ev)) {
         switch (ev->type) {

@@ -504,6 +508,7 @@
     ds->dpy_update = sdl_update;
     ds->dpy_resize = sdl_resize;
     ds->dpy_refresh = sdl_refresh;
+    ds->refresh_interval = 10;
 
     sdl_resize(ds, 640, 400);
     sdl_update_caption();

diff -ur kvm-27.orig/qemu/vl.c kvm-27/qemu/vl.c
@@ -110,7 +110,7 @@
 #define DEFAULT_RAM_SIZE 128
 #endif
 /* in ms */
-#define GUI_REFRESH_INTERVAL 30
+#define DEFAULT_GUI_REFRESH_INTERVAL 30
 
 /* Max number of USB devices that can be specified on the commandline.  */
 #define MAX_USB_CMDLINE 8

@@ -133,6 +133,7 @@
 static DisplayState display_state;
 int nographic;
 const char* keyboard_layout = NULL;
+int sdl_decimate = 3;
 int64_t ticks_per_sec;
 int boot_device = 'c';
 int ram_size;

@@ -4137,6 +4138,7 @@
     ds->dpy_update = dumb_update;
     ds->dpy_resize = dumb_resize;
     ds->dpy_refresh = dumb_refresh;
+    ds->refresh_interval = DEFAULT_GUI_REFRESH_INTERVAL;
 }
 
 /***********************************************************/

@@ -5989,7 +5991,7 @@
 void gui_update(void *opaque)
 {
     display_state.dpy_refresh(&display_state);
-    qemu_mod_timer(gui_timer, GUI_REFRESH_INTERVAL + qemu_get_clock(rt_clock));
+    qemu_mod_timer(gui_timer, display_state.refresh_interval + qemu_get_clock(rt_clock));
 }
 
 struct vm_change_state_entry {

@@ -6342,6 +6344,7 @@
            "-snapshot       write to temporary files instead of disk image files\n"
 #ifdef CONFIG_SDL
            "-no-quit        disable SDL window close capability\n"
+           "-sdl-decimate n refresh display every n*10 milliseconds (default n=3)\n"
 #endif
 #ifdef TARGET_I386
            "-no-fd-bootchk  disable boot signature checking for floppy disks\n"

@@ -6541,6 +6544,9 @@
     QEMU_OPTION_no_rtc,
 #endif
     QEMU_OPTION_cpu_vendor,
+#ifdef CONFIG_SDL
+    QEMU_OPTION_sdl_decimate,
+#endif
 };
 
 typedef struct QEMUOption {

@@ -6616,6 +6622,7 @@
     { "full-screen", 0, QEMU_OPTION_full_screen },
 #ifdef CONFIG_SDL
     { "no-quit", 0, QEMU_OPTION_no_quit },
+    { "sdl-decimate", HAS_ARG, QEMU_OPTION_sdl_decimate },
 #endif
     { "pidfile", HAS_ARG, QEMU_OPTION_pidfile },
     { "win2k-hack", 0, QEMU_OPTION_win2k_hack },

@@ -7189,6 +7196,11 @@
 	    case QEMU_OPTION_k:
 		keyboard_layout = optarg;
 		break;
+	    case QEMU_OPTION_sdl_decimate:
+		sdl_decimate = atoi(optarg);
+		if (sdl_decimate <= 0 || sdl_decimate > 5)
+		    help();
+		break;
             case QEMU_OPTION_localtime:
                 rtc_utc = 0;
                 break;

diff -ur kvm-27.orig/qemu/vl.h kvm-27/qemu/vl.h
@@ -156,6 +156,7 @@
 extern int graphic_height;
 extern int graphic_depth;
 extern const char *keyboard_layout;
+extern int sdl_decimate;
 extern int kqemu_allowed;
 extern int kvm_allowed;
 extern int win2k_install_hack;

@@ -901,6 +902,7 @@
     int width;
     int height;
     void *opaque;
+    int refresh_interval;
 
     void (*dpy_update)(struct DisplayState *s, int x, int y, int w, int h);
     void (*dpy_resize)(struct DisplayState *s, int w, int h);

diff -ur kvm-33.orig/qemu/sdl.c kvm-33/qemu/sdl.c
@@ -43,6 +43,8 @@
 static SDL_Cursor *sdl_cursor_normal;
 static SDL_Cursor *sdl_cursor_hidden;
 static int absolute_enabled = 0;
+static int decimate_counter = 0;
+static int idle_counter = 0;
 
 static void sdl_update(DisplayState *ds, int x, int y, int w, int h)
 {

@@ -311,17 +313,24 @@
     vga_hw_update();
 }
 
+#define SDL_IDLE_THRESHOLD 10
+#define SDL_DECIMATE 3
+
 static void sdl_refresh(DisplayState *ds)
 {
     SDL_Event ev1, *ev = &ev1;
     int mod_state;
+    int was_idle = 1;
                      
     if (last_vm_running != vm_running) {
         last_vm_running = vm_running;
         sdl_update_caption();
     }
 
-    vga_hw_update();
+    if (idle_counter < SDL_IDLE_THRESHOLD || decimate_counter == 0)
+	vga_hw_update();
+
+    decimate_counter = (decimate_counter + 1) % SDL_DECIMATE;
 
     while (SDL_PollEvent(ev)) {
         switch (ev->type) {

@@ -330,6 +339,7 @@
             break;
         case SDL_KEYDOWN:
         case SDL_KEYUP:
+	    was_idle = 0;
             if (ev->type == SDL_KEYDOWN) {
                 mod_state = (SDL_GetModState() & gui_grab_code) ==
                     gui_grab_code;

@@ -428,6 +438,7 @@
             }
             break;
         case SDL_MOUSEMOTION:
+	    was_idle = 0;
             if (gui_grab || kbd_mouse_is_absolute() ||
                 absolute_enabled) {
                 sdl_send_mouse_event(0);

@@ -435,6 +446,7 @@
             break;
         case SDL_MOUSEBUTTONDOWN:
         case SDL_MOUSEBUTTONUP:
+	    was_idle = 0;
             {
                 SDL_MouseButtonEvent *bev = &ev->button;
                 if (!gui_grab && !kbd_mouse_is_absolute()) {

@@ -467,6 +479,13 @@
             break;
         }
     }
+
+    if (was_idle) {
+	if (idle_counter < SDL_IDLE_THRESHOLD)
+	    idle_counter++;
+    } else {
+	idle_counter = 0;
+    }
 }
 
 static void sdl_cleanup(void) 

@@ -504,6 +523,7 @@
     ds->dpy_update = sdl_update;
     ds->dpy_resize = sdl_resize;
     ds->dpy_refresh = sdl_refresh;
+    ds->refresh_interval = 10;
 
     sdl_resize(ds, 640, 400);
     sdl_update_caption();

diff -ur kvm-33.orig/qemu/vl.c kvm-33/qemu/vl.c
@@ -110,7 +110,7 @@
 #define DEFAULT_RAM_SIZE 128
 #endif
 /* in ms */
-#define GUI_REFRESH_INTERVAL 30
+#define DEFAULT_GUI_REFRESH_INTERVAL 30
 
 /* Max number of USB devices that can be specified on the commandline.  */
 #define MAX_USB_CMDLINE 8

@@ -4137,6 +4137,7 @@
     ds->dpy_update = dumb_update;
     ds->dpy_resize = dumb_resize;
     ds->dpy_refresh = dumb_refresh;
+    ds->refresh_interval = DEFAULT_GUI_REFRESH_INTERVAL;
 }
 
 /***********************************************************/

@@ -5995,7 +5996,7 @@
 void gui_update(void *opaque)
 {
     display_state.dpy_refresh(&display_state);
-    qemu_mod_timer(gui_timer, GUI_REFRESH_INTERVAL + qemu_get_clock(rt_clock));
+    qemu_mod_timer(gui_timer, display_state.refresh_interval + qemu_get_clock(rt_clock));
 }
 
 struct vm_change_state_entry {

diff -ur kvm-33.orig/qemu/vl.h kvm-33/qemu/vl.h
@@ -907,6 +907,7 @@
     int width;
     int height;
     void *opaque;
+    int refresh_interval;
 
     void (*dpy_update)(struct DisplayState *s, int x, int y, int w, int h);
     void (*dpy_resize)(struct DisplayState *s, int w, int h);