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,DKIM_SIGNED, DKIM_VALID,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 47BBAC433DF for ; Wed, 12 Aug 2020 14:56:30 +0000 (UTC) Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BF2422080C for ; Wed, 12 Aug 2020 14:56:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alsa-project.org header.i=@alsa-project.org header.b="c5x7zWlA" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BF2422080C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=alsa-devel-bounces@alsa-project.org Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id ECF8F84B; Wed, 12 Aug 2020 16:55:37 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz ECF8F84B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1597244188; bh=9Gw/jXVDOO/cWfQw2yxa8E078c+Bt0Jx9RlFahwfBZY=; h=Date:From:To:Subject:In-Reply-To:References:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=c5x7zWlA+ek8dNujFcTHP7VAky/eXeRIxnJGwG5h3e6tIT9d49N+XXipb+u+mTGLA yYp5Y53o9qr07FRW9l+gDKOubLUuBoDB6oYVz36TwmltHwZONQY49xCd6X1CAN39Jc E9AySFlEETkFuGVsTihTCZx4Cp9Ukg2OWv4KpB9k= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 9530EF800D3; Wed, 12 Aug 2020 16:55:37 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 6C423F8022B; Wed, 12 Aug 2020 16:55:36 +0200 (CEST) Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 9E3C6F800D3 for ; Wed, 12 Aug 2020 16:55:29 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 9E3C6F800D3 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 2CD5CAC1C; Wed, 12 Aug 2020 14:55:51 +0000 (UTC) Date: Wed, 12 Aug 2020 16:55:29 +0200 Message-ID: From: Takashi Iwai To: Pierre-Louis Bossart Subject: Re: [PATCH v3 2/2] ASoC: Intel: Add period size constraint on strago board In-Reply-To: References: <3f3baf5e-f73d-9cd6-cbfb-36746071e126@linux.intel.com> <20200811145353.GG6967@sirena.org.uk> <20200811172209.GM6967@sirena.org.uk> 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 Cc: Guennadi Liakhovetski , "alsa-devel@alsa-project.org" , Kai Vehmanen , Kuninori Morimoto , "Rojewski, Cezary" , Takashi Iwai , Jie Yang , Yu-Hsuan Hsu , "linux-kernel@vger.kernel.org" , Liam Girdwood , Sam McNally , Mark Brown , "yuhsuan@google.com" , Ranjani Sridharan , Daniel Stuart , Andy Shevchenko , "Lu, Brent" , Damian van Soelen X-BeenThere: alsa-devel@alsa-project.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: "Alsa-devel" On Wed, 12 Aug 2020 16:46:40 +0200, Pierre-Louis Bossart wrote: > > > >>>>>> After doing some experiments, I think I can identify the problem more precisely. > >>>>>> 1. aplay can not reproduce this issue because it writes samples > >>>>>> immediately when there are some space in the buffer. However, you can > >>>>>> add --test-position to see how the delay grows with period size 256. > >>>>>>> aplay -Dhw:1,0 --period-size=256 --buffer-size=480 /dev/zero -d 1 -f dat --test-position > >>>>>> Playing raw data '/dev/zero' : Signed 16 bit Little Endian, Rate 48000 > >>>>>> Hz, Stereo > >>>>>> Suspicious buffer position (1 total): avail = 0, delay = 2064, buffer = 512 > >>>>>> Suspicious buffer position (2 total): avail = 0, delay = 2064, buffer = 512 > >>>>>> Suspicious buffer position (3 total): avail = 0, delay = 2096, buffer = 512 > >>>>>> ... > >>>>> > >>>>> Isn't this about the alignment of the buffer size against the period > >>>>> size, not the period size itself? i.e. in the example above, the > >>>>> buffer size isn't a multiple of period size, and DSP can't handle if > >>>>> the position overlaps the buffer size in a half way. > >>>>> > >>>>> If that's the problem (and it's an oft-seen restriction), the right > >>>>> constraint is > >>>>> snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS); > >>>>> > >>>>> > >>>>> Takashi > >>>> Oh sorry for my typo. The issue happens no matter what buffer size is > >>>> set. Actually, even if I want to set 480, it will change to 512 > >>>> automatically. > >>>> Suspicious buffer position (1 total): avail = 0, delay = 2064, buffer > >>>> = 512 <-this one is the buffer size > >>> > >>> OK, then it means that the buffer size alignment is already in place. > >>> > >>> And this large delay won't happen if you use period size 240? > >>> > >>> > >>> Takashi > >> Yes! If I set the period size to 240, it will not print "Suspicious > >> buffer position ..." > > > > So it sounds like DSP handles the delay report incorrectly. > > Then it comes to another question: the driver supports both SOF and > > SST. Is there the behavior difference between both DSPs wrt this > > delay issue? > > I still don't get what the issue is. The two following cases work fine > with the SST/Atom driver: > > root@chrx:~# aplay -Dhw:0,0 --period-size=240 --buffer-size=480 > /dev/zero -d 2 -f dat --test-position > Playing raw data '/dev/zero' : Signed 16 bit Little Endian, Rate 48000 > Hz, Stereo > root@chrx:~# aplay -Dhw:0,0 --period-size=960 --buffer-size=4800 > /dev/zero -d 2 -f dat --test-position > Playing raw data '/dev/zero' : Signed 16 bit Little Endian, Rate 48000 > Hz, Stereo What if with --period-size=256 --buffer-size=512 and --test-position? Can you reproduce the problem in your side? > The existing code has this: > > /* Make sure, that the period size is always even */ > snd_pcm_hw_constraint_step(substream->runtime, 0, > SNDRV_PCM_HW_PARAM_PERIODS, 2); > > return snd_pcm_hw_constraint_integer(runtime, > SNDRV_PCM_HW_PARAM_PERIODS); > > and with the addition of period size being a multiple of 1ms all > requirements should be met? I also wonder what's really missing, too :) BTW, I took a look back at the thread, and CRAS seems using a very large buffer, namely: [ 52.434791] sound pcmC1D0p: PERIOD_SIZE [240:240] [ 52.434802] sound pcmC1D0p: BUFFER_SIZE [204480:204480] Takashi