winex11: Add error checks around every XF86VidMode call.

dlls/winex11.drv/xvidmode.c

@@ -203,19 +203,20 @@ void X11DRV_XF86VM_Init(void)
   /* see if XVidMode is available */
   wine_tsx11_lock();
   ok = pXF86VidModeQueryExtension(gdi_display, &xf86vm_event, &xf86vm_error);
-  if (ok)
-  {
+  wine_tsx11_unlock();
+  if (!ok) return;
+
   X11DRV_expect_error(gdi_display, XVidModeErrorHandler, NULL);
   ok = pXF86VidModeQueryVersion(gdi_display, &xf86vm_major, &xf86vm_minor);
-      if (X11DRV_check_error()) ok = FALSE;
-  }
-  if (ok)
-  {
+  if (X11DRV_check_error() || !ok) return;
+
 #ifdef X_XF86VidModeSetGammaRamp
   if (xf86vm_major > 2 || (xf86vm_major == 2 && xf86vm_minor >= 1))
   {
+      X11DRV_expect_error(gdi_display, XVidModeErrorHandler, NULL);
       pXF86VidModeGetGammaRampSize(gdi_display, DefaultScreen(gdi_display),
                                    &xf86vm_gammaramp_size);
+      if (X11DRV_check_error()) xf86vm_gammaramp_size = 0;
       if (xf86vm_gammaramp_size == 256)
           xf86vm_use_gammaramp = TRUE;
   }
@@ -223,12 +224,12 @@ void X11DRV_XF86VM_Init(void)
 
   /* retrieve modes */
   if (usexvidmode && root_window == DefaultRootWindow( gdi_display ))
+  {
+      X11DRV_expect_error(gdi_display, XVidModeErrorHandler, NULL);
       ok = pXF86VidModeGetAllModeLines(gdi_display, DefaultScreen(gdi_display), &nmodes, &real_xf86vm_modes);
-      else
-          ok = FALSE; /* In desktop mode, do not switch resolution... But still use the Gamma ramp stuff */
+      if (X11DRV_check_error() || !ok) return;
   }
-  wine_tsx11_unlock();
-  if (!ok) return;
+  else return; /* In desktop mode, do not switch resolution... But still use the Gamma ramp stuff */
 
   TRACE("XVidMode modes: count=%d\n", nmodes);