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=-5.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 13F22C433DF for ; Tue, 11 Aug 2020 14:54:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D47C520855 for ; Tue, 11 Aug 2020 14:54:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597157666; bh=Zl1pJ2DFMmfKMyJErLFYhmOgyXO6PRB0VQI/KuGEDw0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=U03R5ka4fyGRi/ciTt3T4rSOm4q8YaqR1J2BfO1i/SZnhUmfQVLZNg4SuFwAtpUeF yB96kmUVAOGXOrWDq943O3zCtEw1mnbhBloBLCTGpx/rip07p5y6hAoRgB9Vrz/0gd AffLrHHu60H71/P22g0SoIesNbCMTGt/yQbi+F/g= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728893AbgHKOyY (ORCPT ); Tue, 11 Aug 2020 10:54:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:56534 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728802AbgHKOyW (ORCPT ); Tue, 11 Aug 2020 10:54:22 -0400 Received: from localhost (fw-tnat.cambridge.arm.com [217.140.96.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B3B492083B; Tue, 11 Aug 2020 14:54:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597157661; bh=Zl1pJ2DFMmfKMyJErLFYhmOgyXO6PRB0VQI/KuGEDw0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=iH7qbb0GzuMV9fPw7/HNe4Txfq+eGeS0iW+h2zR9twWkwrCwj6bRX/czJr6xvZmxO BJhNNJLU0wdnPYenJjKjIfSaNWPOJfypoLhQb4DrxzJtSR5eW4EKVvcU3DmrjWI4kE ZJXvf1YeXxKuNSeNN5/3K+lEqj30omp1+1UMbIKw= Date: Tue, 11 Aug 2020 15:53:53 +0100 From: Mark Brown To: Yu-Hsuan Hsu Cc: Takashi Iwai , "Lu, Brent" , Guennadi Liakhovetski , "alsa-devel@alsa-project.org" , Andy Shevchenko , Kuninori Morimoto , Kai Vehmanen , "linux-kernel@vger.kernel.org" , "Rojewski, Cezary" , Jie Yang , Pierre-Louis Bossart , Takashi Iwai , Liam Girdwood , Sam McNally , Ranjani Sridharan , Daniel Stuart , "yuhsuan@google.com" , Damian van Soelen Subject: Re: [PATCH v3 2/2] ASoC: Intel: Add period size constraint on strago board Message-ID: <20200811145353.GG6967@sirena.org.uk> References: <6466847a-8aae-24f7-d727-36ba75e95f98@linux.intel.com> <3f3baf5e-f73d-9cd6-cbfb-36746071e126@linux.intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="5L6AZ1aJH5mDrqCQ" Content-Disposition: inline In-Reply-To: X-Cookie: Gravity is a myth, the Earth sucks. User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --5L6AZ1aJH5mDrqCQ Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Aug 11, 2020 at 05:35:45PM +0800, Yu-Hsuan Hsu wrote: > Takashi Iwai =E6=96=BC 2020=E5=B9=B48=E6=9C=8811=E6=97=A5= =E9=80=B1=E4=BA=8C =E4=B8=8B=E5=8D=884:39=E5=AF=AB=E9=81=93=EF=BC=9A > > ... Why only 240? That's the next logical question. > > If you have a clarification for it, it may be the rigid reason to > > introduce such a hw constraint. > According to Brent, the DSP is using 240 period regardless the > hw_param. If the period size is 256, DSP will read 256 samples each > time but only consume 240 samples until the ring buffer of DSP is > full. This behavior makes the samples in the ring buffer of kernel > consumed quickly. > Not sure whether the explanation is correct. Hi Brent, can you confirm it? This seems to be going round and round in circles. Userspace lets the kernel pick the period size, if the period size isn't 240 (or a multiple of it?) the DSP doesn't properly pay attention to that apparently due to internal hard coding in the DSP firmware which we can't change so the constraint logic needs to know about this DSP limitation - it seems like none of this is going to change without something new going into the mix? We at least need a new question to ask about the DSP firmware I think. --5L6AZ1aJH5mDrqCQ Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAl8ysQAACgkQJNaLcl1U h9AeeAf/UWVHZwuLSbdU4F24gTh9Evg65nXjOQ/J9iQI9FUTAWaZmBBgfnbWlbRx 1sqvxQ03kOtC40oS9jFz0hYMwDMQm4seHQfg9Zy0gr6DUHcZBnh+eTmn//6u6Xto W68Wr61drakKTT+9jqC5j694fxtAl1uAvrySfjiIoAJFUg+JRsytjzaeUWRGY1+z 9EjA+q5dX7LuwPKxUmkPkSipJwxXF4zateJ3VnKK2dmNvtnFbYAYD+b7FK2x+9sK Q30ZaYcs5rlAif136+aUFKABTBjVBjxzE1yGlD66ZipYapXuFo1IyGiQWwq2phPT ZRU1vj4Zn9eW/Ma7XKCxMWgxJHEoOg== =CfWE -----END PGP SIGNATURE----- --5L6AZ1aJH5mDrqCQ--