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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5C252CDB483 for ; Thu, 19 Oct 2023 18:42:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345224AbjJSSm4 (ORCPT ); Thu, 19 Oct 2023 14:42:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43344 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233020AbjJSSmz (ORCPT ); Thu, 19 Oct 2023 14:42:55 -0400 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 656B9126; Thu, 19 Oct 2023 11:42:53 -0700 (PDT) Received: from pps.filterd (m0279872.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 39JHLeYc017772; Thu, 19 Oct 2023 18:42:24 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h=message-id : date : mime-version : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding; s=qcppdkim1; bh=+WYtO5cbSnOWSh4A3pWMM/G3dupE15Bp2QKlH1BzWsI=; b=nT+MmY2WzSPKW196i552YTH0gwyJZGiZFYXUqprsFbil4DZFgftzvGeEKVvtUYaJAuGA huN0YQQjWNiQxTBRtKOTZeBhCEfRJ1tMhBBBn7ly5a3/CJTqGGw6q0F0Nu/bhogk/eCj dfhBZz7M3gqqWRzcleJk5qT2TAhsNipbDp/VXxkTMsMcD29Los9LHhRUmivk5de8tn8V yUDhfQI/UejhX4nCJS0olgOh9OQ2mlPz/qjuiigwRt3EuzxQQlq0Bvaq6drtH1jC7Olb TiTHgqy7GkJ4x4/67NmIiTiOQHtSafjQysNEJEmO3wUiaO/dksSr0JLXefRGG4iasLzO IQ== Received: from nalasppmta04.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3ttg82ums4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 19 Oct 2023 18:42:24 +0000 Received: from nalasex01b.na.qualcomm.com (nalasex01b.na.qualcomm.com [10.47.209.197]) by NALASPPMTA04.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 39JIgNob007271 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 19 Oct 2023 18:42:23 GMT Received: from [10.110.99.208] (10.80.80.8) by nalasex01b.na.qualcomm.com (10.47.209.197) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.39; Thu, 19 Oct 2023 11:42:22 -0700 Message-ID: Date: Thu, 19 Oct 2023 11:42:22 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH v9 09/34] ASoC: qcom: qdsp6: Introduce USB AFE port to q6dsp Content-Language: en-US To: Pierre-Louis Bossart , , , , , , , , , , , , , , , CC: , , , , References: <20231017200109.11407-1-quic_wcheng@quicinc.com> <20231017200109.11407-10-quic_wcheng@quicinc.com> <7aa4ea87-9d1f-400a-bcc5-b56e5b4500c6@linux.intel.com> <2f05708e-3ee8-472e-a24f-6f3eb118133c@linux.intel.com> From: Wesley Cheng In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.80.80.8] X-ClientProxiedBy: nasanex01b.na.qualcomm.com (10.46.141.250) To nalasex01b.na.qualcomm.com (10.47.209.197) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: k5nkufEfbNCtKUCx8FQH5sYfnPcPKmKk X-Proofpoint-ORIG-GUID: k5nkufEfbNCtKUCx8FQH5sYfnPcPKmKk X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.980,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-10-19_17,2023-10-19_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_spam policy=outbound score=65 clxscore=1015 impostorscore=0 mlxlogscore=-26 spamscore=65 priorityscore=1501 adultscore=0 bulkscore=0 mlxscore=65 suspectscore=0 lowpriorityscore=0 phishscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2309180000 definitions=main-2310190159 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Pierre, On 10/18/2023 6:00 PM, Pierre-Louis Bossart wrote: > > >>>>>> Specifically, the QC ADSP can support all potential endpoints that are >>>>>> exposed by the audio data interface.  This includes, feedback >>>>>> endpoints >>>>>> (both implicit and explicit) as well as the isochronous (data) >>>>>> endpoints. >>>>> >>>>> implicit feedback means support for capture. This is confusing... >>>>> >>>> >>>> I mean, a USB device can expose a capture path, but as of now, we won't >>>> enable the offloading to the audio DSP for it.  However, if we're >>>> executing playback, and device does support implicit feedback, we will >>>> pass that along to the audio DSP to utilize. >>> >>> Not following. Implicit feedback means a capture stream *SHALL* be >>> started. Are you saying this capture stream is hidden and handled at the >>> DSP level only? If yes, what prevents you from exposing the capture >>> stream to userspace as well? >>> >>> I must be missing something. >>> >> >> My understanding is that with implicit feedback endpoints, it allows for >> another data endpoint in the opposite direction to be utilized as a >> feedback endpoint (versus having to expose another EP, such as in the >> case of explicit feedback).  For example, if we are enabling the >> playback path (and the device does have a capture data ep) then the data >> ep used for the capture path can be used. > > That's right, so all the plumbing is enabled for the capture path... > Making a decision to discard the data is very odd, all the work has > already been done at lower levels, so why not expose the captured data? > So that would be at the USB level, but from the audio DSP end, there are still things that need to be enabled to route the data properly. For feedback endpoints, the data we're actually sending won't involve the audio streaming side of things on the DSP. Thanks Wesley Cheng