Add workaround for xgl being unresponsive on high CPU load

ChangeLog

@@ -1,5 +1,9 @@
 2006-03-20  David Reveman  <davidr@novell.com>
 
+	* hw/xgl/xglinit.c: Add workaround for xgl being unresponsive on
+	nvidia's driver when something that consumes a lot of CPU is running
+	in the background.
+
 	* hw/xgl/glxext/xglglxext.c: Update for rendering to FBOs. Adjust
 	clipping and draw/read offsets when FBO is bound. Lookup texture and
 	renderbuffer objects when attaching. Fix

hw/xgl/xglinit.c

@@ -331,6 +331,21 @@ OsVendorInit (void)
 	(*__ddxFunc.osVendorInit) ();
 }
 
-void ddxInitGlobals()
+void
+ddxInitGlobals (void)
 {
 }
+
+#if 1
+
+/* nvdia's driver seem to be abusing sched_yield and it is causing
+   xgl to be very unresponsive if something that consumes a lot of CPU
+   is running in the background. having this empty implementation of
+   sched_yield here is an ugly workaround that seem to make things
+   work a lot better. */
+void
+sched_yield (void)
+{
+}
+
+#endif