From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752133AbbJNHWj (ORCPT ); Wed, 14 Oct 2015 03:22:39 -0400 Received: from www.linutronix.de ([62.245.132.108]:53414 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751320AbbJNHWh (ORCPT ); Wed, 14 Oct 2015 03:22:37 -0400 Date: Wed, 14 Oct 2015 09:21:42 +0200 (CEST) From: Thomas Gleixner To: Richard Cochran cc: "Christopher S. Hall" , jeffrey.t.kirsher@intel.com, hpa@zytor.com, mingo@redhat.com, john.stultz@linaro.org, peterz@infradead.org, x86@kernel.org, intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kevin.b.stanton@intel.com Subject: Re: [PATCH v4 1/4] Produce system time from correlated clocksource In-Reply-To: <20151013211224.GA19242@netboy> Message-ID: References: <1444675522-4198-1-git-send-email-christopher.s.hall@intel.com> <1444675522-4198-2-git-send-email-christopher.s.hall@intel.com> <20151013045832.GA2437@netboy> <20151013083113.GA1931@localhost.localdomain> <20151013211224.GA19242@netboy> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 13 Oct 2015, Richard Cochran wrote: > On Tue, Oct 13, 2015 at 09:15:51PM +0200, Thomas Gleixner wrote: > > That's not working. The firmware is not going to change, no matter > > what. > > Can we at least have a explanation of how the firmware operates? How > are (ART,sys) pairs are generated, and how they are supposed to get > into the DSP? The firmware gives you an ART/audio timestamp pair. The firmware does neither know about system time nor about PTP time. So we have to do correlation in software. Thanks, tglx