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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id D7352FAD40B for ; Thu, 23 Apr 2026 05:06:27 +0000 (UTC) Received: from alsa1.perex.cz (alsa1.perex.cz [45.14.194.44]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 719C660204; Thu, 23 Apr 2026 07:06:15 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 719C660204 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1776920785; bh=XbNo9ez4QCom4Wza0xYVSYZJHZPha+NYGVoo0OJkRvU=; h=Date:Subject:From:To:Cc:References:In-Reply-To:List-Id: List-Archive:List-Help:List-Owner:List-Post:List-Subscribe: List-Unsubscribe:From; b=sGluEWSBBAVirLFzi2UonuUTBlWGODBFKZY6Nv3HadZuw3xGd1dpDtP6PjuX+sWdd ygy+hSqxCkJHN7+xZ6yVwwkHkfJjKHVtW99RKMXUWoirXcAYTTgex8RO/WIQQGuJ0C EQeomWIad48O0XaC2zPSsym8XkgaU2cQmkHzsAT4= Received: by alsa1.perex.cz (Postfix, from userid 50401) id EC465F805C3; Thu, 23 Apr 2026 07:05:52 +0200 (CEST) Received: from mailman-core.alsa-project.org (mailman-core.alsa-project.org [10.254.200.10]) by alsa1.perex.cz (Postfix) with ESMTP id 74F86F805C3; Thu, 23 Apr 2026 07:05:52 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 2B93EF80526; Thu, 23 Apr 2026 07:05:45 +0200 (CEST) Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.14]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 9F267F80162 for ; Thu, 23 Apr 2026 07:05:40 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 9F267F80162 Authentication-Results: alsa1.perex.cz; dkim=pass (2048-bit key, unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=ZbifwyVD DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1776920743; x=1808456743; h=message-id:date:mime-version:subject:from:to:cc: references:in-reply-to:content-transfer-encoding; bh=XbNo9ez4QCom4Wza0xYVSYZJHZPha+NYGVoo0OJkRvU=; b=ZbifwyVDcC9Zgy0J1UhShLg4VJHy7Dmr6962PfUBQyOiotkIhCkppYi2 DCYwVTIGDZYwuuOD25ZVygw65rkZG/13V67b3ZGJpifLyvxLJY5onrJKM z9i1fU1WDvQ8Lwfy5uf4XrJXd6iBQ5B3+PmNiciCFsFYsmQsj75KQJv0G /Okano/lTolCzwtEx0rS0l5hxMHk4x3s+98QakL/FDCtf4rR8X4AgHjnB dKSeAQOY3FCtFN1PV+iDfHZ7NZ+5twWUzCuxDCxDr9lKGWr7HOwr09P54 cxr0wwMt6tuzt6idJoHh+NbTcsb/ARZ6/lMJAQlyxzfzFM4+T9HvUxR7B A==; X-CSE-ConnectionGUID: Pj8k4ugTRyGkixYz1PYUow== X-CSE-MsgGUID: 8T2ZiNssSdi2Y3m3cb5cAg== X-IronPort-AV: E=McAfee;i="6800,10657,11764"; a="81745406" X-IronPort-AV: E=Sophos;i="6.23,194,1770624000"; d="scan'208";a="81745406" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by orvoesa106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Apr 2026 22:05:36 -0700 X-CSE-ConnectionGUID: FXcxBodXRfa426+jizs9gA== X-CSE-MsgGUID: bLmGRteXRJW8p6tFqPjhVg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,194,1770624000"; d="scan'208";a="256035501" Received: from fpallare-mobl4.ger.corp.intel.com (HELO [10.245.244.105]) ([10.245.244.105]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Apr 2026 22:05:34 -0700 Message-ID: <463d844b-ef44-471a-8749-6bb068833c4a@linux.intel.com> Date: Thu, 23 Apr 2026 08:05:30 +0300 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: (re)use and (re)definition of snd_pcm_hw_params->fifo_size for 'jumpy DMA' From: =?UTF-8?Q?P=C3=A9ter_Ujfalusi?= To: Jaroslav Kysela , Takashi Iwai Cc: Takashi Iwai , Mark Brown , Liam Girdwood , Linux-ALSA , "linux-sound@vger.kernel.org" , Kai Vehmanen , arun@asymptotic.io, wim.taymans@gmail.com References: <87se9htms4.wl-tiwai@suse.de> <67b9f48b-1cc7-4dac-8f6a-c0cba6a84b36@linux.intel.com> <87ikadtgpe.wl-tiwai@suse.de> <878qb8tsib.wl-tiwai@suse.de> <88979231-caef-4eaa-b89d-22e6973c92f9@perex.cz> <4c73e4cb-298a-411a-97ed-f0eff1b06ac9@linux.intel.com> <978bdc67-b91e-437a-bb8a-b609a4fef6d1@perex.cz> <82d870b3-4ec1-440a-ae8b-87edbf665b99@perex.cz> <542a9743-2a47-477a-b457-ae32c3f8dc49@linux.intel.com> <39fcca55-77f4-4cd9-8a94-d80e5b94c8ba@perex.cz> <401a7777-e83c-4120-9d82-71388bf38397@linux.intel.com> <8af520bc-cb27-416a-b823-7a21f0784f89@linux.intel.com> Content-Language: en-US In-Reply-To: <8af520bc-cb27-416a-b823-7a21f0784f89@linux.intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Message-ID-Hash: 5H6EO62G5QDMZF75OGB7XBAZESGVYORT X-Message-ID-Hash: 5H6EO62G5QDMZF75OGB7XBAZESGVYORT X-MailFrom: peter.ujfalusi@linux.intel.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; header-match-alsa-devel.alsa-project.org-0; header-match-alsa-devel.alsa-project.org-1; emergency; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.10 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On 22/04/2026 17:19, Péter Ujfalusi wrote: > Hrm, so this is a driver scoped refine, right? Based on the requested > period size and a flag (SNDRV_PCM_HW_PARAMS_LATENCY_AWARE?) the driver > refines the period size based on it's jumpyDMA capabilities? > > But in this example the application will have no knowledge still how the > DMA will move, the DMA will initially move 30ms and after that, every > 5ms it moves 5ms, so the driver should be refining to 5ms period size, 6 > initial periods and 1 period step, no. > > Or with my favorite examples: > 4ms initial burst w/ 1ms steps will refine to 1ms periods, 4 init and 1 > step. > 100ms initial burst w/ 96ms steps will refine to... I'm not sure 4ms period size, 25 init periods, 24 step periods? and same for > 40ms initial burst w/ 36ms steps. 4ms period size, 10 init periods, 9 step periods? -- Péter