From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752505AbcFVMhk (ORCPT ); Wed, 22 Jun 2016 08:37:40 -0400 Received: from mga14.intel.com ([192.55.52.115]:15581 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751453AbcFVMhi (ORCPT ); Wed, 22 Jun 2016 08:37:38 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.26,509,1459839600"; d="scan'208";a="1002993375" Subject: Re: [alsa-devel] [very-RFC 0/8] TSN driver for the kernel To: Richard Cochran References: <20160613114713.GA9544@localhost.localdomain> <20160613195136.GC2441@netboy> <20160614121844.54a125a5@lxorguk.ukuu.org.uk> <5760C84C.40408@sakamocchi.jp> <20160615080602.GA13555@localhost.localdomain> <5764DA85.3050801@sakamocchi.jp> <20160618224549.GF32724@icarus.home.austad.us> <9a5abd48-4da3-945d-53c9-b6d37010ab0d@linux.intel.com> <20160620121838.GA5257@localhost.localdomain> <07283da9-f6d1-c3b1-7989-a6fce7ca0ee6@linux.intel.com> <20160621194001.GB2489@netboy> Cc: alsa-devel@alsa-project.org, netdev@vger.kernel.org, Henrik Austad , linux-kernel@vger.kernel.org, Takashi Sakamoto , Arnd Bergmann , linux-media@vger.kernel.org From: Pierre-Louis Bossart Message-ID: <04675515-ff64-0acc-f0f0-7714e20c1485@linux.intel.com> Date: Wed, 22 Jun 2016 05:36:42 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: <20160621194001.GB2489@netboy> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/21/16 12:40 PM, Richard Cochran wrote: > On Tue, Jun 21, 2016 at 10:45:18AM -0700, Pierre-Louis Bossart wrote: >> You can experiment with the 'dma' and 'link' timestamps today on any >> HDaudio-based device. Like I said the synchronized part has not been >> upstreamed yet (delays + dependency on ART-to-TSC conversions that made it >> in the kernel recently) > > Can you point me to any open source apps using the dma/link > timestamps? Those timestamps are only used in custom applications at the moment, not 'mainstream' open source. It takes time for new kernel capabilities to trickle into userspace, applications usually align on the lowest hardware common denominator. In addition, most applications don't access the kernel directly but go through an audio server or HAL which needs to be updated as well so it's a two-level dependency. These timestamps can be directly mappped to the Android AudioTrack.getTimeStamp API though.