From mboxrd@z Thu Jan 1 00:00:00 1970 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 smtp.subspace.kernel.org (Postfix) with ESMTPS id 249DF29BD82 for ; Thu, 23 Apr 2026 05:05:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.14 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776920738; cv=none; b=QMXRMSOpMEpCE1Rv9snjnkPnm02wjaKKQCCALLsgkFpal/ZjLKe94GAuYsxUQD4/lwT9PsfcGCpP38kVso+PFP7w2qrK+W9JRCgw+rMXMC3j22kAgWpSu4sPH9W/w+ucwroK1VmkebsulPgtOerJX6rbtkxsrGwEYlsl5yTJfPw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776920738; c=relaxed/simple; bh=XbNo9ez4QCom4Wza0xYVSYZJHZPha+NYGVoo0OJkRvU=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=NE04XQYX+i9wpn+cDO3NMGIX990Ktk+5PYYx4wn0Pnrfc+QKPT45Jk6v4H8PNuZie9sYGbp3H3kUExPXitI1+W1+RGoMIXqFjVCbH8ETjgslwYz1mRZbSUHIQj7w2r07vuP4CKJtSgluVtBAm9IcLbrHB26bs00WFB3ons2Ng8w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=CPgM0Uwp; arc=none smtp.client-ip=198.175.65.14 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="CPgM0Uwp" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1776920737; x=1808456737; h=message-id:date:mime-version:subject:from:to:cc: references:in-reply-to:content-transfer-encoding; bh=XbNo9ez4QCom4Wza0xYVSYZJHZPha+NYGVoo0OJkRvU=; b=CPgM0Uwpol/HSQqyg1WHvY3Ob0s9OfDhJz5/0bw597HN3NLUJPppYZF9 /TfKAaN3c8buainFjUeoU0RcUhRwYMZ4kK4Bcz8lPcJtGoV6hDfGTfdsa bi3G9sm97+PUf1QOgROVWjgfs1yPWRC/NvP3x0bbFoPEnxQikkdV/7N8L EXj+qhpKqAiDw3RmmLn69WA34x+DYrYxZsS9kQ942VdqmcfmwMnm51v2e i4SR6Tm1NDqH4zXO12/+ZtnVgeaRuEZla22k70iefuTNMucFRKqCui5pT wGHjk2tCQ0aSqMDaULGxV3Rsz7M/R9vIi80Y9F8exgySocyk6pqE4BVRL g==; X-CSE-ConnectionGUID: V1qjaXFFTvibeYagf25+Eg== X-CSE-MsgGUID: yoihYLcfTBOvZi32UA8W7A== X-IronPort-AV: E=McAfee;i="6800,10657,11764"; a="81745404" X-IronPort-AV: E=Sophos;i="6.23,194,1770624000"; d="scan'208";a="81745404" 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 Precedence: bulk X-Mailing-List: linux-sound@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 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