From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751750AbcFNLS4 (ORCPT ); Tue, 14 Jun 2016 07:18:56 -0400 Received: from lxorguk.ukuu.org.uk ([81.2.110.251]:35488 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751153AbcFNLSy (ORCPT ); Tue, 14 Jun 2016 07:18:54 -0400 Date: Tue, 14 Jun 2016 12:18:44 +0100 From: One Thousand Gnomes To: Richard Cochran Cc: Henrik Austad , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, alsa-devel@vger.kernel.org, netdev@vger.kernel.org, henrk@austad.us, Arnd Bergmann Subject: Re: [very-RFC 0/8] TSN driver for the kernel Message-ID: <20160614121844.54a125a5@lxorguk.ukuu.org.uk> In-Reply-To: <20160613195136.GC2441@netboy> References: <1465686096-22156-1-git-send-email-henrik@austad.us> <20160613114713.GA9544@localhost.localdomain> <20160613195136.GC2441@netboy> Organization: Intel Corporation X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 13 Jun 2016 21:51:36 +0200 Richard Cochran wrote: > On Mon, Jun 13, 2016 at 01:47:13PM +0200, Richard Cochran wrote: > > 3. ALSA support for tunable AD/DA clocks. The rate of the Listener's > > DA clock must match that of the Talker and the other Listeners. > > Either you adjust it in HW using a VCO or similar, or you do > > adaptive sample rate conversion in the application. (And that is > > another reason for *not* having a shared kernel buffer.) For the > > Talker, either you adjust the AD clock to match the PTP time, or > > you measure the frequency offset. > > Actually, we already have support for tunable clock-like HW elements, > namely the dynamic posix clock API. It is trivial to write a driver > for VCO or the like. I am just not too familiar with the latest high > end audio devices. Why high end ? Even the most basic USB audio is frame based and isosynchronous to the USB clock. It also reports back the delay properties. Alan