From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frank Li Subject: Lower wake up time when phy enter lower mode Date: Wed, 7 Nov 2012 10:52:32 +0800 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 To: Richard Cochran , netdev@vger.kernel.org Return-path: Received: from mail-ia0-f174.google.com ([209.85.210.174]:46422 "EHLO mail-ia0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752708Ab2KGCwe (ORCPT ); Tue, 6 Nov 2012 21:52:34 -0500 Received: by mail-ia0-f174.google.com with SMTP id y32so791118iag.19 for ; Tue, 06 Nov 2012 18:52:34 -0800 (PST) Sender: netdev-owner@vger.kernel.org List-ID: Richard: Recently, I found out the path delay will increase about 20us suddenly in something when connect two iMX6 board and Ethernet work on 1G mode. The reason is that the PHY enter lower mode automatically when no package send and receive. It takes some time to recover and send out package by PHY but MAC think package have sent and sample time stamper. Do you meet such case? I can workaround it by two method 1. disable phy lower power feature. 2. add some dummy package before SYNC package. Best regards Frank Li