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 27F55C433DF for ; Wed, 12 Aug 2020 06:14:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 05F6D2076B for ; Wed, 12 Aug 2020 06:14:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726586AbgHLGOC (ORCPT ); Wed, 12 Aug 2020 02:14:02 -0400 Received: from mx2.suse.de ([195.135.220.15]:54180 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725944AbgHLGOC (ORCPT ); Wed, 12 Aug 2020 02:14:02 -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 B1D51AC12; Wed, 12 Aug 2020 06:14:21 +0000 (UTC) Date: Wed, 12 Aug 2020 08:13:59 +0200 Message-ID: From: Takashi Iwai To: Yu-Hsuan Hsu Cc: Mark Brown , Pierre-Louis Bossart , Guennadi Liakhovetski , "alsa-devel@alsa-project.org" , Kai Vehmanen , Kuninori Morimoto , "Rojewski, Cezary" , Takashi Iwai , Jie Yang , "linux-kernel@vger.kernel.org" , Liam Girdwood , Sam McNally , "yuhsuan@google.com" , Ranjani Sridharan , Daniel Stuart , Andy Shevchenko , "Lu, Brent" , Damian van Soelen 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=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 12 Aug 2020 05:09:58 +0200, Yu-Hsuan Hsu wrote: > > Mark Brown 於 2020年8月12日 週三 上午1:22寫道： > > > > On Tue, Aug 11, 2020 at 11:54:38AM -0500, Pierre-Louis Bossart wrote: > > > > > > 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. > > > > > I just tested aplay -Dhw: on a Cyan Chromebook with the Ubuntu kernel 5.4, > > > and I see no issues with the 240 sample period. Same with 432, 960, 9600, > > > etc. > > > > > I also tried just for fun what happens with 256 samples, and I don't see any > > > underflows thrown either, so I am wondering what exactly the problem is? > > > Something's not adding up. I would definitively favor multiple of 1ms > > > periods, since it's the only case that was productized, but there's got to > > > me something a side effect of how CRAS programs the hw_params. > > > > Is it something that goes wrong with longer playbacks possibly (eg, > > someone watching a feature film or something)? > > Thanks for testing! > > 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 > 2. Since many samples are moved to DSP(delay), the measured rate of > the ring-buffer is high. (I measured it by alsa_conformance_test, > which only test the sampling rate in the ring buffer of kernel not > DSP) > > 3. Since CRAS writes samples with a fixed frequency, this behavior > will take all samples from the ring buffer, which is seen as underrun > by CRAS. (It seems that it is not a real underrun because that avail > does not larger than buffer size. Maybe CRAS should also take dalay > into account.) > > 4. In spite of it is not a real underrun, the large delay is still a > big problem. Can we apply the constraint to fix it? Or any better > idea? > > Thanks, > Yu-Hsuan > 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 F096DC433DF for ; Wed, 12 Aug 2020 06:15:05 +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 7CAFE2076B for ; Wed, 12 Aug 2020 06:15:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alsa-project.org header.i=@alsa-project.org header.b="j/mgXBJe" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7CAFE2076B 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 DD66B1662; Wed, 12 Aug 2020 08:14:13 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz DD66B1662 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1597212903; bh=FexQohZPWb/INxmBncAfApR6S7sR/WWv7YkBqRcHU1I=; h=Date:From:To:Subject:In-Reply-To:References:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=j/mgXBJeWgJ74M9ZajfG7izTBcUniJZRpmixmo+Yo3WummeOzNrvOQPJ3BK6E0Key uxu6rLMelOP//QFN/aZx3aLsCE2qiTzQCQIq9hFB556BEfFdrtVPnuYwTPEstUTgkh rUGTcsry3TT9vYu7jiLyL96X0qB4zzzRQW5xjP4M= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 77FD3F800D3; Wed, 12 Aug 2020 08:14:13 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 298A7F8022B; Wed, 12 Aug 2020 08:14:12 +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 08FA2F800D3 for ; Wed, 12 Aug 2020 08:14:00 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 08FA2F800D3 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 B1D51AC12; Wed, 12 Aug 2020 06:14:21 +0000 (UTC) Date: Wed, 12 Aug 2020 08:13:59 +0200 Message-ID: From: Takashi Iwai To: Yu-Hsuan Hsu 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=UTF-8 Content-Transfer-Encoding: 8bit Cc: 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 , Mark Brown , Ranjani Sridharan , Daniel Stuart , "yuhsuan@google.com" , "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 05:09:58 +0200, Yu-Hsuan Hsu wrote: > > Mark Brown 於 2020年8月12日 週三 上午1:22寫道： > > > > On Tue, Aug 11, 2020 at 11:54:38AM -0500, Pierre-Louis Bossart wrote: > > > > > > 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. > > > > > I just tested aplay -Dhw: on a Cyan Chromebook with the Ubuntu kernel 5.4, > > > and I see no issues with the 240 sample period. Same with 432, 960, 9600, > > > etc. > > > > > I also tried just for fun what happens with 256 samples, and I don't see any > > > underflows thrown either, so I am wondering what exactly the problem is? > > > Something's not adding up. I would definitively favor multiple of 1ms > > > periods, since it's the only case that was productized, but there's got to > > > me something a side effect of how CRAS programs the hw_params. > > > > Is it something that goes wrong with longer playbacks possibly (eg, > > someone watching a feature film or something)? > > Thanks for testing! > > 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 > 2. Since many samples are moved to DSP(delay), the measured rate of > the ring-buffer is high. (I measured it by alsa_conformance_test, > which only test the sampling rate in the ring buffer of kernel not > DSP) > > 3. Since CRAS writes samples with a fixed frequency, this behavior > will take all samples from the ring buffer, which is seen as underrun > by CRAS. (It seems that it is not a real underrun because that avail > does not larger than buffer size. Maybe CRAS should also take dalay > into account.) > > 4. In spite of it is not a real underrun, the large delay is still a > big problem. Can we apply the constraint to fix it? Or any better > idea? > > Thanks, > Yu-Hsuan >