From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) (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 DD76680055; Thu, 9 May 2024 21:38:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.180.131 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715290709; cv=none; b=c6NuruEdNkK8N2YddgZKk8ewDlzXK4UKU396snyhFbwi/XHq3szyFqmNXw6Iupv7rPr3ALWAQvYz2IA8f+RKuNenI8DbogU2zr0i+MnDcOq4JIFLWeYX/oNa5Yz2upSwzeNnsJCXfVoPi0x3najWOhdhgbaJ2SMja1uhK1QH74w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715290709; c=relaxed/simple; bh=yWPX1AFHH2oExxi38GsDYw2RAIkGJktuI3QA9EyICcA=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=kMz1XhJY+NqtqQuX4tcNAxxmjGrOdQDhBqR5M+GhWf34RTilPlH0aKUcKfn21aZkaNa/NEDdFKPt/8piQs9PVSrYc40i0xBE9mOXtTxiZWqxR/B3Cz9B/wxbv4ZSfFFPqy8bL/TSMefTxV/yR/WTgUrOHqYgNpDTh+JwsQ/X/fA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=quicinc.com; spf=pass smtp.mailfrom=quicinc.com; dkim=pass (2048-bit key) header.d=quicinc.com header.i=@quicinc.com header.b=FnW1WTQd; arc=none smtp.client-ip=205.220.180.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=quicinc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=quicinc.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=quicinc.com header.i=@quicinc.com header.b="FnW1WTQd" Received: from pps.filterd (m0279870.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 449KsuID020451; Thu, 9 May 2024 21:38:06 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=pAqbv8FC1GGiAfW8jfg1f2NttdRya0AXcZ6HKnPki+8=; b=Fn W1WTQdGqe13RoyGRQKo+QXs+ltPSNGAdsVaaFE2m5jx2NU0wmprUpAk86p2dH43A 4xgajmSMkzygbE6YiQdNdN1kS5WhfrC5S3zqQNpcPQhlnKufNHprJAaUoW4awJvz v5h38ZSOhY/PILcnK9JGvCAqYMQ7C8qPhd2/JlQeImcOCJUkMwD0+CEcFUFf02cA wXGYm30O+AOCNYxMWnp41LTUqIbjc1qZNcDsj1nx+MZ4IcJTbKSSDrRo8eQrckjH YxUjWNuzO+LZCFpi8QHijTgB8UM959VwC5LHXpavN897cKb7daSwu0ikQAOzKtZ4 Arhu9UJg63+p68lSEeXw== Received: from nalasppmta05.qualcomm.com (Global_NAT1.qualcomm.com [129.46.96.20]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 3y09ejupn1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 09 May 2024 21:38:05 +0000 (GMT) Received: from nalasex01b.na.qualcomm.com (nalasex01b.na.qualcomm.com [10.47.209.197]) by NALASPPMTA05.qualcomm.com (8.17.1.5/8.17.1.5) with ESMTPS id 449Lc3IH021191 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 9 May 2024 21:38:03 GMT Received: from [10.71.112.114] (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 15.2.1544.9; Thu, 9 May 2024 14:38:02 -0700 Message-ID: <21ead53d-773b-ab8c-2d7d-cf4419b9a7ea@quicinc.com> Date: Thu, 9 May 2024 14:38:01 -0700 Precedence: bulk X-Mailing-List: linux-sound@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Subject: Re: [PATCH v21 22/39] ALSA: usb-audio: Prevent starting of audio stream if in use Content-Language: en-US To: Pierre-Louis Bossart , , , , , , , , , , , , , , , , CC: , , , , , , References: <20240507195116.9464-1-quic_wcheng@quicinc.com> <20240507195116.9464-23-quic_wcheng@quicinc.com> <1e98935e-e35a-49e0-bbbf-ff326d40b581@linux.intel.com> <066fe096-a9d3-2498-275d-185f709e9a02@quicinc.com> From: Wesley Cheng In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit 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: bKrP1y1Vmj7qvp-m7b477taU24e9uToI X-Proofpoint-ORIG-GUID: bKrP1y1Vmj7qvp-m7b477taU24e9uToI X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.650,FMLib:17.11.176.26 definitions=2024-05-09_12,2024-05-09_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 suspectscore=0 adultscore=0 spamscore=0 mlxscore=0 lowpriorityscore=0 priorityscore=1501 clxscore=1015 mlxlogscore=822 malwarescore=0 bulkscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2405010000 definitions=main-2405090152 Hi Pierre, On 5/9/2024 6:01 AM, Pierre-Louis Bossart wrote: > > > On 5/8/24 18:40, Wesley Cheng wrote: >> Hi Pierre, >> >> On 5/7/2024 2:20 PM, Pierre-Louis Bossart wrote: >>> >>>> If a PCM device is already in use, the check will return an error to >>>> userspace notifying that the stream is currently busy.  This ensures >>>> that >>>> only one path is using the USB substream. >>> >>> What was the point of having a "USB Mixer" then? >> >> The USB mixer is intended to enable/route the USB offloading path to the >> audio DSP, and is for controlling the ASoC specific entities.  This >> change is needed to resolve any contention between the USB SND PCM >> device (non offload path) and the ASoC USB BE DAI (offload path). > > Not following, sorry. Is the "USB Mixer" some sort of hardware entity > related to USB offload or just a pure DAPM processing widget handling > volume and actual mixing between streams? > It controls which Multimedia (ASM) stream can be routed to the USB BE DAI. > I was trying to get clarity on whether there can be multiple streams > mixed before going to the USB endpoint. The commit message "only one > path is using the USB substream" is ambiguous, not sure if you are > referring to mutual exclusion between offloaded and non-offloaded paths, > or number of streams when offloaded is supported. Different concepts/levels. Ideally we shouldn't. Only one ASM stream should be allowed to open the USB AFE port at a time. Thanks Wesley Cheng