From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Cochran Subject: Re: [PATCH v2 1/1] net: fec: ptp: avoid register access when ipg clock is disabled Date: Thu, 14 Aug 2014 10:10:36 +0200 Message-ID: <20140814081036.GB7555@netboy> References: <1407905705-27984-1-git-send-email-b38611@freescale.com> <1407905705-27984-2-git-send-email-b38611@freescale.com> <20140813211941.GB4840@netboy> <4dcf48cd1c11473c82fcec0c8963ece2@BLUPR03MB373.namprd03.prod.outlook.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "shawn.guo@linaro.org" , "davem@davemloft.net" , "netdev@vger.kernel.org" To: "fugang.duan@freescale.com" Return-path: Received: from mail-wi0-f171.google.com ([209.85.212.171]:54020 "EHLO mail-wi0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751078AbaHNIKl (ORCPT ); Thu, 14 Aug 2014 04:10:41 -0400 Received: by mail-wi0-f171.google.com with SMTP id hi2so8512478wib.4 for ; Thu, 14 Aug 2014 01:10:40 -0700 (PDT) Content-Disposition: inline In-Reply-To: <4dcf48cd1c11473c82fcec0c8963ece2@BLUPR03MB373.namprd03.prod.outlook.com> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, Aug 14, 2014 at 01:28:28AM +0000, fugang.duan@freescale.com wrote: > If the ethx close, ptp stack cannot run normally, stack stop send sync message with master, But this has no effect on whether transmit time stamps are enabled. The timer work must run whenever the (physical) clock is running. Otherwise you will have discontinuities in your PTP clock. The kernel must always behave correctly, regardless of what user space does. When the user calls clock_gettime(), the result must always be consistent. This has nothing to do with time stamping at all. Thanks, Richard