kvm tools: Use double buffering with SDL

Page flip every time we copy the buffer over instead of invalidating
rects.
This should improve performance by letting hardware do the page
flipping.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

diff --git a/tools/kvm/ui/sdl.c b/tools/kvm/ui/sdl.c
index bf2f7c9888ffdefc9f54682b71afb3fa158bc0e2..aa3eff9102672331d38c459c22fa0d6804e15950 100644 (file)
--- a/tools/kvm/ui/sdl.c
+++ b/tools/kvm/ui/sdl.c
@@ -91,7 +91,7 @@ static void *sdl__thread(void *p)
        if (!guest_screen)
                die("Unable to create SDL RBG surface");
 
-       flags = SDL_HWSURFACE | SDL_ASYNCBLIT | SDL_HWACCEL;
+       flags = SDL_HWSURFACE | SDL_ASYNCBLIT | SDL_HWACCEL | SDL_DOUBLEBUF;
 
        screen = SDL_SetVideoMode(fb->width, fb->height, fb->depth, flags);
        if (!screen)
@@ -99,7 +99,7 @@ static void *sdl__thread(void *p)
 
        for (;;) {
                SDL_BlitSurface(guest_screen, NULL, screen, NULL);
-               SDL_UpdateRect(screen, 0, 0, 0, 0);
+               SDL_Flip(screen);
 
                while (SDL_PollEvent(&ev)) {
                        switch (ev.type) {