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=-5.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 A8779C41604 for ; Wed, 7 Oct 2020 16:44:01 +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 528A0206BE for ; Wed, 7 Oct 2020 16:43:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alsa-project.org header.i=@alsa-project.org header.b="WEyy86Zb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 528A0206BE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com 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 228B216CB; Wed, 7 Oct 2020 18:43:06 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 228B216CB DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1602089036; bh=Zi21e3lFPGQmHN3kupBq1PluqPEh6Unn018cWCe57q4=; h=Subject:To:References:From:Date:In-Reply-To:Cc:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From; b=WEyy86ZbSDnN7va+3nIcQyjmAkHZ1eVtfQj00FOs2NSGOfIw+XjiQjpepNtujL/xR ayG42QvxTd3ij4L0nqwp0WXb7Wz5UC97NSSH/6g2rGvXY45/0OykzzVBf9AVdsEwR+ Ril7IOkiESWS4rUUtZZMv9VGbCDPSl8n2j52Ldlk= Received: from alsa1.perex.cz (localhost.localdomain [127.0.0.1]) by alsa1.perex.cz (Postfix) with ESMTP id EE241F80090; Wed, 7 Oct 2020 18:42:49 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 6C3D2F8016D; Wed, 7 Oct 2020 18:42:47 +0200 (CEST) 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 CCFDCF80128 for ; Wed, 7 Oct 2020 18:42:39 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz CCFDCF80128 IronPort-SDR: 2hIcxsTLcz+oV4y736BupSZVsNzREN44xPnTNO5QEKba2oiuV9xc3ZP4X56/et1nmSSXtmjBDw vEiPHAJT8Pyg== X-IronPort-AV: E=McAfee;i="6000,8403,9767"; a="144398663" X-IronPort-AV: E=Sophos;i="5.77,347,1596524400"; d="scan'208";a="144398663" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Oct 2020 09:42:30 -0700 IronPort-SDR: UFXGdHsYPIRIyk1795uoKnQYBLg1V+gAwtUWg0EZLMRsdsO+HRA4YzpfgVjIfMVGj/0+1SRl2v KzAPsBED5bAg== X-IronPort-AV: E=Sophos;i="5.77,347,1596524400"; d="scan'208";a="528044888" Received: from npurusho-mobl.amr.corp.intel.com (HELO [10.212.194.22]) ([10.212.194.22]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Oct 2020 09:42:28 -0700 Subject: Re: [PATCH 0/6] Ancillary bus implementation and SOF multi-client support To: Mark Brown , Dan Williams References: <20200930225051.889607-1-david.m.ertman@intel.com> <20201001071403.GC31191@kroah.com> <20201003090855.GD114893@kroah.com> <20201005112547.GA401816@kroah.com> <20201007091443.GA822254@kroah.com> <20201007162251.GB5030@sirena.org.uk> From: Pierre-Louis Bossart Message-ID: <10048d4d-038c-c2b7-2ed7-fd4ca87d104a@linux.intel.com> Date: Wed, 7 Oct 2020 11:42:26 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201007162251.GB5030@sirena.org.uk> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Cc: "alsa-devel@alsa-project.org" , "tiwai@suse.de" , "gregkh@linuxfoundation.org" , "Sridharan, Ranjani" , "parav@nvidia.com" , "jgg@nvidia.com" , "Ertman, David M" 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" >>> "virtual" here means "not real" :) > >> Which of these aux device use cases is not a real device? One of my >> planned usages for this facility is for the NPEM (Native PCIE >> Enclosure Management) mechanism that can appear on any PCIE >> bridge/endpoint. While it is true that the NPEM register set does not >> get its own PCI-b:d:f address on the host bus, it is still >> discoverable by a standard enumeration scheme. It is real auxiliary >> device functionality that can appear on any PCIE device where the >> kernel can now have one common NPEM driver for all instances in the >> topology. > > Some if not all of the SOF cases are entirely software defined by the > firmware downloaded to the audio DSPs. Correct for DSP processing/debug stuff. In some cases though, the firmware deals with different IOs (HDMI, I2C) and having multiple 'aux' devices helps expose unrelated physical functions in a more modular way. The non-SOF audio case I can think of is SoundWire. We want to expose SoundWire links as separate devices even though they are not exposed in the platform firmware or PCI configs (decision driven by Windows). We currently use platform devices for this, but we'd like to transition to this 'aux' bus