From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 54AE0C433E0 for ; Mon, 3 Aug 2020 16:56:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2DBEE20722 for ; Mon, 3 Aug 2020 16:56:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727015AbgHCQ4f (ORCPT ); Mon, 3 Aug 2020 12:56:35 -0400 Received: from mx2.suse.de ([195.135.220.15]:40300 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726356AbgHCQ4f (ORCPT ); Mon, 3 Aug 2020 12:56:35 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 19217AB71; Mon, 3 Aug 2020 16:56:49 +0000 (UTC) Date: Mon, 03 Aug 2020 18:56:33 +0200 Message-ID: From: Takashi Iwai To: "Lu, Brent" Cc: Pierre-Louis Bossart , Guennadi Liakhovetski , "alsa-devel@alsa-project.org" , "Kuninori Morimoto" , Kai Vehmanen , "Rojewski, Cezary" , Jie Yang , "linux-kernel@vger.kernel.org" , Takashi Iwai , Liam Girdwood , "Sam McNally" , Mark Brown , "Ranjani Sridharan" , Daniel Stuart , Andy Shevchenko , Yu-Hsuan Hsu , Damian van Soelen , "yuhsuan@google.com" Subject: Re: [PATCH v3 2/2] ASoC: Intel: Add period size constraint on strago board In-Reply-To: References: <1596020585-11517-1-git-send-email-brent.lu@intel.com> <1596198365-10105-1-git-send-email-brent.lu@intel.com> <1596198365-10105-3-git-send-email-brent.lu@intel.com> <63bca214-3434-16c6-1b60-adf323aec554@linux.intel.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 03 Aug 2020 18:45:29 +0200, Lu, Brent wrote: > > > > Hi Takashi, > > > > > > I've double checked with google. It's a must for Chromebooks due to > > > low latency use case. > > > > I wonder if there's a misunderstanding here? > > > > I believe Takashi's question was "is this a must to ONLY accept 240 samples > > for the period size", there was no pushback on the value itself. > > Are those boards broken with e.g. 960 samples? > > I've added google people to discuss directly. > > Hi Yuhsuan, > Would you explain why CRAS needs to use such short period size? Thanks. For avoid further misunderstanding: it's fine that CRAS *uses* such a short period. It's often required for achieving a short latency. However, the question is whether the driver can set *only* this value for making it working. IOW, if we don't have this constraint, what actually happens? If the driver gives the period size alignment, wouldn't CRAS choose 240? Takashi