WaitForInput before trying to xf86EloGetPacket. #14109

Followup to 72408c2404.

This patch isn't perfect yet, usage of O_NONBLOCK would be preferred and some
better error handling for incomplete packages, but at least it's less broken
than without this patch.

Signed-off-by: Peter Hutterer <peter@cs.unisa.edu.au>

X.Org Bug 14109 <http://bugs.freedesktop.org/show_bug.cgi?id=14109>

src/xf86Elo.c

@@ -807,10 +807,13 @@ xf86EloReadInput(LocalDevicePtr	local)
   /*
    * Try to get a packet.
    */
-  while (xf86EloGetPacket(priv->packet_buf,
+  while (xf86WaitForInput(local->fd, ELO_MAX_WAIT) > 0) {
+      if(xf86EloGetPacket(priv->packet_buf,
 		       &priv->packet_buf_p,
 		       &priv->checksum,
-		       local->fd) == Success) {
+		       local->fd) != Success)
+          break;
+
       /*
        * Process only ELO_TOUCHs here.
        */