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=-3.7 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 84B33C2BA1A for ; Fri, 24 Apr 2020 06:29:07 +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 0DA6920706 for ; Fri, 24 Apr 2020 06:29:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alsa-project.org header.i=@alsa-project.org header.b="arFY1aHJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0DA6920706 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 5FFD3168F; Fri, 24 Apr 2020 08:28:15 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 5FFD3168F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1587709745; bh=0sKTfX0R59E+J/xxNTbHYBdkkUaiAB5U5XXpSKNDRiU=; h=Date:From:To:Subject:In-Reply-To:References:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=arFY1aHJCF0olZFN1g5p5Z/rKuzRAyrtirnfz5LTL2CYGlmuskFRdzDqSPIqClUB7 rw8EKEYuxHthV2EBeAevUS8qxxKkmn37hiGTl9+W1UpYBQMna9PDcIC60MvJqmcMC6 zF21LGrGvMTMvCmgBVrQnPXPEpC/E/fKTXjMLmY8= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id CDB27F800BE; Fri, 24 Apr 2020 08:28:14 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 99C16F80142; Fri, 24 Apr 2020 08:28:10 +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 C603DF800BE for ; Fri, 24 Apr 2020 08:28:05 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz C603DF800BE X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 46798ADCD; Fri, 24 Apr 2020 06:28:02 +0000 (UTC) Date: Fri, 24 Apr 2020 08:28:02 +0200 Message-ID: From: Takashi Iwai To: Alexander Tsoy Subject: Re: [PATCH 1/2] ALSA: usb-audio: Improve frames size computation In-Reply-To: <20200424022449.14972-1-alexander@tsoy.me> References: <20200424022449.14972-1-alexander@tsoy.me> 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: Gregor Pintar , alsa-devel@alsa-project.org, Roope Salmi 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 Fri, 24 Apr 2020 04:24:48 +0200, Alexander Tsoy wrote: > > For computation of the the next frame size current value of fs/fps and > accumulated fractional parts of fs/fps are used, where values are stored > in Q16.16 format. This is quite natural for computing frame size for > asynchronous endpoints driven by explicit feedback, since in this case > fs/fps is a value provided by the feedback endpoint and it's already in > the Q format. If an error is accumulated over time, the device can > adjust fs/fps value to prevent buffer overruns/underruns. > > But for synchronous endpoints the accuracy provided by these computations > is not enough. Due to accumulated error the driver periodically produces > frames with incorrect size (+/- 1 audio sample). > > This patch fixes this issue by implementing a different algorithm for > frame size computation. It is based on accumulating of the remainders > from division fs/fps and it doesn't accumulate errors over time. This > new method is enabled for synchronous and adaptive playback endpoints. > > Signed-off-by: Alexander Tsoy Applied to for-next branch now. thanks, Takashi