From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Cochran Subject: Re: [PATCH net-next] dp83640: Adjust ptp event timestamps Date: Thu, 10 Jul 2014 19:34:39 +0200 Message-ID: <20140710173439.GB7965@localhost.localdomain> References: <1404901343-19445-1-git-send-email-stefan.sorensen@spectralink.com> <20140709174149.GA3859@localhost.localdomain> <1404983629.2901.8.camel@e37108.spectralink.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "netdev@vger.kernel.org" To: =?iso-8859-1?B?U/hyZW5zZW4s?= Stefan Return-path: Received: from mail-wg0-f52.google.com ([74.125.82.52]:35131 "EHLO mail-wg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751213AbaGJRfE (ORCPT ); Thu, 10 Jul 2014 13:35:04 -0400 Received: by mail-wg0-f52.google.com with SMTP id b13so9174707wgh.23 for ; Thu, 10 Jul 2014 10:35:01 -0700 (PDT) Content-Disposition: inline In-Reply-To: <1404983629.2901.8.camel@e37108.spectralink.com> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, Jul 10, 2014 at 09:13:51AM +0000, S=F8rensen, Stefan wrote: > This is not adjusting the packet timestamps but the gpio event > timestamps - the ptp protocol is not involved here. Without this > adjustment, looping back a pps signal from one gpio to another will > result in a ~35ns offset. Oops, sorry. =20 > Then the end user will have to figure out what delay corrections need= to > be made and configure the applications(s) to adjust for this. But I > don't see any good solution to this either.=20 Yep, not so easy. I think it is only practical in a highly controlled environment. Thanks, Richard