Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932775AbbHXUQz (ORCPT ); Mon, 24 Aug 2015 16:16:55 -0400 Received: from mga03.intel.com ([134.134.136.65]:34375 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932683AbbHXUQw convert rfc822-to-8bit (ORCPT ); Mon, 24 Aug 2015 16:16:52 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,740,1432623600"; d="scan'208";a="754583428" From: "Hall, Christopher S" To: "'Richard Cochran'" , Thomas Gleixner CC: "Kirsher, Jeffrey T" , "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" Subject: RE: [PATCH v3 3/4] Add support for driver cross-timestamp to PTP_SYS_OFFSET ioctl Thread-Topic: [PATCH v3 3/4] Add support for driver cross-timestamp to PTP_SYS_OFFSET ioctl Thread-Index: AQHQ3H1BVsJU+XrIXka6HnG7M4xba54Y8BAAgAAMJwCAALfDAIAANVgAgAGoYsA= Date: Mon, 24 Aug 2015 20:16:51 +0000 Message-ID: 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> <20150823112556.GA8569@localhost.localdomain> In-Reply-To: <20150823112556.GA8569@localhost.localdomain> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.22.254.140] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1883 Lines: 47 > -----Original Message----- > From: Richard Cochran [mailto:richardcochran@gmail.com] > Sent: Sunday, August 23, 2015 4:26 AM > To: Thomas Gleixner > Cc: Hall, Christopher S; Kirsher, Jeffrey T; 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 > Subject: Re: [PATCH v3 3/4] Add support for driver cross-timestamp to > PTP_SYS_OFFSET ioctl > > 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. This means: remove code changes from the PTP_SYS_OFFSET ioctl and call getsynctime64() from a new ioctl PTP_SYS_OFFSET_PRECISE. Right? And use the same type (struct ptp_sys_offset) for the new ioctl? Or should a new simplified struct be used? Such as: struct precise_ptp_sys_offset { struct ptp_clock_time device; struct ptp_clock_time system; }; Does it make sense to keep the "cross-timestamp" capabilities flag as-is? > > Thanks, > Richard -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/