From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Cochran Subject: Re: [PATCH v3 3/4] Add support for driver cross-timestamp to PTP_SYS_OFFSET ioctl Date: Sun, 23 Aug 2015 13:25:56 +0200 Message-ID: <20150823112556.GA8569@localhost.localdomain> References: <1440183128-1384-1-git-send-email-christopher.s.hall@intel.com> <1440183128-1384-4-git-send-email-christopher.s.hall@intel.com> <20150822211718.GA8561@netboy> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "Christopher S. Hall" , jeffrey.t.kirsher@intel.com, hpa@zytor.com, mingo@redhat.com, john.stultz@linaro.org, x86@kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, intel-wired-lan@lists.osuosl.org, peterz@infradead.org To: Thomas Gleixner Return-path: Received: from mail-wi0-f178.google.com ([209.85.212.178]:33845 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751916AbbHWL0D (ORCPT ); Sun, 23 Aug 2015 07:26:03 -0400 Content-Disposition: inline In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Sun, Aug 23, 2015 at 10:15:00AM +0200, Thomas Gleixner wrote: > So why can't you take N samples from the synced hardware? It does not > make any sense to me to switch to the imprecise mode if nsamples > 1. Ok, then I prefer to leave this "imprecise" method in place and ... > You can also provide a new IOCTL PTP_SYS_OFFSET_PRECISE which returns > -ENOSYS if hardware timestamping is not available and avoid the whole > nsamples dance for the case where we can get precise timestamps. have this for the new way. By keeping the imprecise method, we will be able to run both methods on the new hardware. That will help to quantify how imprecise the old method is. Thanks, Richard