From ae23cd00170baaa2777eb1ee87b70f472dbb3c44 Mon Sep 17 00:00:00 2001 From: Gert Wollny Date: Wed, 11 Sep 2024 09:14:30 +0000 Subject: [PATCH] ui/sdl2: set swap interval explicitly when OpenGL is enabled MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Before 176e3783f2ab (ui/sdl2: OpenGL window context) SDL_CreateRenderer was called unconditionally setting the swap interval to 0. Since SDL_CreateRenderer is now no longer called when OpenGL is enabled, the swap interval is no longer set explicitly and vsync handling depends on the environment settings which may lead to a performance regression with virgl as reported in https://gitlab.com/qemu-project/qemu/-/issues/2565 Restore the old vsync handling by explicitly calling SDL_GL_SetSwapInterval if OpenGL is enabled. Fixes: 176e3783f2ab (ui/sdl2: OpenGL window context) Closes: https://gitlab.com/qemu-project/qemu/-/issues/2565 Signed-off-by: Gert Wollny Acked-by: Marc-André Lureau Message-ID: <01020191e05ce6df-84da6386-62c2-4ce8-840e-ad216ac253dd-000000@eu-west-1.amazonses.com> Signed-off-by: Philippe Mathieu-Daudé --- ui/sdl2.c | 1 + 1 file changed, 1 insertion(+) diff --git a/ui/sdl2.c b/ui/sdl2.c index e4cb66c5da..bd4f5a9da1 100644 --- a/ui/sdl2.c +++ b/ui/sdl2.c @@ -115,6 +115,7 @@ void sdl2_window_create(struct sdl2_console *scon) SDL_SetHint(SDL_HINT_RENDER_BATCHING, "1"); scon->winctx = SDL_GL_CreateContext(scon->real_window); + SDL_GL_SetSwapInterval(0); } else { /* The SDL renderer is only used by sdl2-2D, when OpenGL is disabled */ scon->real_renderer = SDL_CreateRenderer(scon->real_window, -1, 0);