Commit 25cd749adba77e1a6f3f31f80f8768c0aaaad5b0
2021-08-12T15:12:04
x11: Don't change mode if we are already in the correct mode If we are already in the desired mode, changing it is a no-op at best, and harmful at worst: on Xwayland, it sometimes happens that we disable the crtc and cannot re-enable it. Resolves: https://github.com/libsdl-org/SDL/issues/4630 Signed-off-by: Simon McVittie <smcv@collabora.com>
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diff --git a/src/video/x11/SDL_x11modes.c b/src/video/x11/SDL_x11modes.c
index 8a9cf56..da520e3 100644
--- a/src/video/x11/SDL_x11modes.c
+++ b/src/video/x11/SDL_x11modes.c
@@ -1040,11 +1040,20 @@ X11_SetDisplayMode(_THIS, SDL_VideoDisplay * sdl_display, SDL_DisplayMode * mode
return SDL_SetError("Couldn't get XRandR crtc info");
}
+ if (crtc->mode == modedata->xrandr_mode) {
+#ifdef X11MODES_DEBUG
+ printf("already in desired mode 0x%lx (%ux%u), nothing to do\n",
+ crtc->mode, crtc->width, crtc->height);
+#endif
+ status = Success;
+ goto freeInfo;
+ }
+
X11_XGrabServer(display);
status = X11_XRRSetCrtcConfig(display, res, output_info->crtc, CurrentTime,
0, 0, None, crtc->rotation, NULL, 0);
if (status != Success) {
- goto setCrtcError;
+ goto ungrabServer;
}
mm_width = mode->w * DisplayWidthMM(display, data->screen) / DisplayWidth(display, data->screen);
@@ -1067,8 +1076,9 @@ X11_SetDisplayMode(_THIS, SDL_VideoDisplay * sdl_display, SDL_DisplayMode * mode
crtc->x, crtc->y, modedata->xrandr_mode, crtc->rotation,
&data->xrandr_output, 1);
-setCrtcError:
+ungrabServer:
X11_XUngrabServer(display);
+freeInfo:
X11_XRRFreeCrtcInfo(crtc);
X11_XRRFreeOutputInfo(output_info);
X11_XRRFreeScreenResources(res);