--- xorg-server-1.7.6.901/hw/xfree86/common/xf86Events.c	2010-04-09 14:23:10.000000000 +0200
+++ xorg-server-1.7.6.901-PATCHED/hw/xfree86/common/xf86Events.c	2010-04-27 22:10:51.000000000 +0200
@@ -104,6 +104,21 @@
 extern void (*xf86OSPMClose)(void);
 #endif

+/* grab debugging */
+static ClientPtr debugGrabClient;
+
+void
+xf86GrabCallback(CallbackListPtr *cbl, void *data, void *closure)
+{
+    ServerGrabInfoRec *grabinfo = data;
+    if (grabinfo == NULL)
+	return;
+    if (grabinfo->grabstate == SERVER_GRABBED)
+	debugGrabClient = grabinfo->client;
+    else if (grabinfo->grabstate == SERVER_UNGRABBED)
+	debugGrabClient = NULL;
+}
+
 static void xf86VTSwitch(void);

 /*
@@ -424,6 +439,26 @@
     }
 }

+static void
+kvetch_about_client(ClientPtr client, DeviceIntPtr device)
+{
+    LocalClientCredRec *lcc;
+
+    ErrorF("Resource mask 0x%08x ", client->clientAsMask);
+
+    if (device) {
+	ErrorF("device name \"%s\" ", device->name);
+    }
+
+    if (GetLocalClientCreds(client, &lcc) != -1) {
+	ErrorF("euid %d egid %d pid %d", lcc->euid, lcc->egid, lcc->pid);
+	FreeLocalClientCreds(lcc);
+    } else {
+	ErrorF("(non-local)");
+    }
+    ErrorF("\n\n");
+}
+
 /*
  * xf86VTSwitch --
  *      Handle requests for switching the vt.
@@ -529,6 +564,30 @@
 	if (xorgHWAccess)
 	    xf86DisableIO();
     }
+
+    /* grab debugging */
+    if (debugGrabClient) {
+	ErrorF("Client holding server grab at VT switch:\n");
+	kvetch_about_client(debugGrabClient, NULL);
+    }
+
+    do {
+	DeviceIntPtr dev;
+	for (dev = inputInfo.devices; dev; dev = dev->next)
+	{
+	    if (dev->deviceGrab.grab)
+		for (i = 0; i < currentMaxClients; i++) {
+			if (clients[i] == NULL)
+				continue;
+			if (CLIENT_BITS(dev->deviceGrab.grab->resource) ==
+				clients[i]->clientAsMask) {
+				ErrorF("Client holding device grab at VT switch:\n");
+				kvetch_about_client(clients[i], dev);
+			}
+		}
+	}
+    } while (0);
+
   } else {

     DebugF("xf86VTSwitch: Entering\n");
--- xorg-server-1.7.6.901/hw/xfree86/common/xf86Init.c	2010-04-09 14:23:31.000000000 +0200
+++ xorg-server-1.7.6.901-PATCHED/hw/xfree86/common/xf86Init.c	2010-04-27 12:35:15.000000000 +0200
@@ -552,6 +552,8 @@

   xf86Initialising = TRUE;

+  DeleteCallback(&ServerGrabCallback, xf86GrabCallback, NULL);
+
   if (serverGeneration == 1) {

     pScreenInfo->numScreens = 0;
@@ -1095,6 +1097,7 @@

   RegisterBlockAndWakeupHandlers((BlockHandlerProcPtr)NoopDDA, xf86Wakeup,
 				 NULL);
+  AddCallback(&ServerGrabCallback, xf86GrabCallback, NULL);
 }

 /*
--- xorg-server-1.7.6.901/hw/xfree86/common/xf86Priv.h	2010-04-09 14:23:10.000000000 +0200
+++ xorg-server-1.7.6.901-PATCHED/hw/xfree86/common/xf86Priv.h	2010-04-27 12:35:15.000000000 +0200
@@ -146,6 +147,8 @@
 extern _X_EXPORT int (*xf86PMGetEventFromOs)(int fd,pmEvent *events,int num);
 extern _X_EXPORT pmWait (*xf86PMConfirmEventToOs)(int fd,pmEvent event);

+extern void xf86GrabCallback(CallbackListPtr *cbl, void *data, void *closure);
+
 /* xf86Helper.c */
 extern _X_EXPORT void xf86LogInit(void);
 extern _X_EXPORT void xf86CloseLog(void);