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 68C07C433EF for ; Mon, 10 Jan 2022 16:50:22 +0000 (UTC) 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 ADB3B18B3; Mon, 10 Jan 2022 17:49:29 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz ADB3B18B3 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1641833419; bh=RD9okIjLSTH7xkAaitQ8zmG3R2QSjQPLZHJurvli5Ng=; h=Subject:To:References:From:Date:In-Reply-To:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=SioReYUv4EygawHzvH9w92NWPeZsfM/slv9BTV3B9mroreO6N+mRbnBY3cthuiU6H UHNFRjXa7GAs2V4jH9pD1Mwvm+aSeiMFR6gpaNp0BiqECF12O2XqfObSs149C9lTSC FUo68KHZt3qBcOCma/ihKf/9mlzPX0HJuDhemKdQ= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id 4689CF80118; Mon, 10 Jan 2022 17:49:29 +0100 (CET) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 0DEBDF8012E; Mon, 10 Jan 2022 17:49:26 +0100 (CET) Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) (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 B19E3F80118 for ; Mon, 10 Jan 2022 17:49:15 +0100 (CET) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz B19E3F80118 Authentication-Results: alsa1.perex.cz; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="K98WA4uS" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1641833358; x=1673369358; h=subject:to:cc:references:from:message-id:date: mime-version:in-reply-to:content-transfer-encoding; bh=RD9okIjLSTH7xkAaitQ8zmG3R2QSjQPLZHJurvli5Ng=; b=K98WA4uS5fkzFUfPmCNzJlDmsUR4G+Fjljz+uSGlzhCtE6UYPd5rNfbS 9xeWN8I6MpvJtkvEFzbru7y21Ui/auNeL1wNLnrk4IBpNyWedGfp+tV8u 1yVQHYKJEUZHFahqxijMTQHeTDaUhaioL0mqbu+2OivDlDvv2thC/AvCw 3yAim7p2yS5WxHcv5TkG5OZQel22q9tYMlhnx+tmJjQynbksXyy+GHqNZ Bs292srCc0uP++FtwEZpHBaPMeARpRSzYc05cAeXJzho3+7rXRLWvtdKM Dqp31CN/WY3KoFO3m9WRey1WgbZ3nkOsrgtfDbDEP0w5J+ElJ/YH9XlRD g==; X-IronPort-AV: E=McAfee;i="6200,9189,10222"; a="223249027" X-IronPort-AV: E=Sophos;i="5.88,277,1635231600"; d="scan'208";a="223249027" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Jan 2022 08:49:12 -0800 X-IronPort-AV: E=Sophos;i="5.88,277,1635231600"; d="scan'208";a="472123479" Received: from boviedox-mobl.amr.corp.intel.com (HELO [10.212.36.191]) ([10.212.36.191]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 Jan 2022 08:49:11 -0800 Subject: Re: [PATCH 7/7] soundwire: intel: remove PDM support To: "Liao, Bard" , Vinod Koul References: <20211213054634.30088-1-yung-chuan.liao@linux.intel.com> <20211213054634.30088-8-yung-chuan.liao@linux.intel.com> From: Pierre-Louis Bossart Message-ID: <0cb18de1-dcff-e3c8-414e-b5b96b30b387@linux.intel.com> Date: Mon, 10 Jan 2022 10:32:32 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Firefox/78.0 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Cc: "alsa-devel@alsa-project.org" , "tiwai@suse.de" , "gregkh@linuxfoundation.org" , "linux-kernel@vger.kernel.org" , "broonie@kernel.org" , "srinivas.kandagatla@linaro.org" , "Kale, Sanyog R" , Bard Liao 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" >>>>> While the hardware supports PDM streams, this capability has never >>>>> been tested or enabled on any product, so this is dead-code. Let's >>>>> remove all this. >>>> >>>> So no plans to test and enable this? Do the DMICs not use PDM? >>> >>> The point is that this code is unused/untested. We can re-add it after >>> it was tested. >> >> That does not answer my question. Do the DMICs not use PDM? > > I will leave the question to Pierre. 😊 traditional digital microphones using the Nokia spec with two microphones using opposite clock edges do use PDM. PDM over SoundWire is possible as well, it's e.g. used by Qualcomm for amplifiers. This patch does not make a statement on whether PDM support makes sense or not in general. As mentioned above on Intel platforms the hardware is in theory capable of supporting PDM, but that capability has never been deployed, all existing devices we connect to are PCM based and all the PDM references are essentially untested - and likely broken.